21655404442260 has 192 divisors, whose sum is σ = 70926141619200. Its totient is φ = 5470232828544.

The previous prime is 21655404442249. The next prime is 21655404442277. The reversal of 21655404442260 is 6224440455612.

21655404442260 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 540 + 4 + 4 + 42 + 2 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 63 ways as a sum of consecutive naturals, for example, 96362547 + ... + 96587013.

It is an arithmetic number, because the mean of its divisors is an integer number (369406987600).

Almost surely, 2^{21655404442260} is an apocalyptic number.

21655404442260 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 21655404442260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35463070809600).

21655404442260 is an abundant number, since it is smaller than the sum of its proper divisors (49270737176940).

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

21655404442260 is a wasteful number, since it uses less digits than its factorization.

21655404442260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233907 (or 233899 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 45.

Adding to 21655404442260 its reverse (6224440455612), we get a palindrome (27879844897872).

The spelling of 21655404442260 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred four million, four hundred forty-two thousand, two hundred sixty".