21065551042656 has 96 divisors (see below), whose sum is σ = 55477211102208. Its totient is φ = 6999012400640.

The previous prime is 21065551042633. The next prime is 21065551042691. The reversal of 21065551042656 is 65624015556012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36302641 + ... + 36878351.

It is an arithmetic number, because the mean of its divisors is an integer number (577887615648).

Almost surely, 2^{21065551042656} is an apocalyptic number.

It is an amenable number.

21065551042656 is an abundant number, since it is smaller than the sum of its proper divisors (34411660059552).

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

21065551042656 is a wasteful number, since it uses less digits than its factorization.

21065551042656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576964 (or 576956 counting only the distinct ones).

The product of its (nonzero) digits is 2160000, while the sum is 48.

Adding to 21065551042656 its reverse (65624015556012), we get a palindrome (86689566598668).

The spelling of 21065551042656 in words is "twenty-one trillion, sixty-five billion, five hundred fifty-one million, forty-two thousand, six hundred fifty-six".