21257118405144 has 256 divisors, whose sum is σ = 62665399872000. Its totient is φ = 6666315102720.

The previous prime is 21257118405139. The next prime is 21257118405209. The reversal of 21257118405144 is 44150481175212.

21257118405144 is a `hidden beast` number, since 2 + 1 + 2 + 57 + 1 + 1 + 84 + 0 + 514 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21257118405144.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 40625167 + ... + 41145089.

It is an arithmetic number, because the mean of its divisors is an integer number (244786718250).

Almost surely, 2^{21257118405144} is an apocalyptic number.

21257118405144 is a gapful number since it is divisible by the number (24) 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 21257118405144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31332699936000).

21257118405144 is an abundant number, since it is smaller than the sum of its proper divisors (41408281466856).

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

21257118405144 is a wasteful number, since it uses less digits than its factorization.

21257118405144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520135 (or 520125 counting only the distinct ones).

The product of its (nonzero) digits is 358400, while the sum is 45.

The spelling of 21257118405144 in words is "twenty-one trillion, two hundred fifty-seven billion, one hundred eighteen million, four hundred five thousand, one hundred forty-four".