21257164938240 has 1760 divisors, whose sum is σ = 95672967667200. Its totient is φ = 4384380026880.

The previous prime is 21257164938223. The next prime is 21257164938253. The reversal of 21257164938240 is 4283946175212.

It is a happy number.

21257164938240 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 71 + 6 + 493 + 82 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1760).

It is a super-2 number, since 2×21257164938240² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 4438745766 + ... + 4438750554.

It is an arithmetic number, because the mean of its divisors is an integer number (54359640720).

It is a 2-persistent number, because it is pandigital, and so is 2⋅21257164938240 = 42514329876480, but 3⋅21257164938240 = 63771494814720 is not.

Almost surely, 2^{21257164938240} is an apocalyptic number.

21257164938240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21257164938240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47836483833600).

21257164938240 is an abundant number, since it is smaller than the sum of its proper divisors (74415802728960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21257164938240 is a wasteful number, since it uses less digits than its factorization.

21257164938240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4983 (or 4956 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 21257164938240 in words is "twenty-one trillion, two hundred fifty-seven billion, one hundred sixty-four million, nine hundred thirty-eight thousand, two hundred forty".