21660553061051 has 8 divisors (see below), whose sum is σ = 21819407313600. Its totient is φ = 21501709649728.

The previous prime is 21660553061039. The next prime is 21660553061057. The reversal of 21660553061051 is 15016035506612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21660553061051 - 2²⁶ = 21660485952187 is a prime.

It is a super-2 number, since 2×21660553061051² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660553061057) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1322225 + ... + 6713373.

It is an arithmetic number, because the mean of its divisors is an integer number (2727425914200).

Almost surely, 2^{21660553061051} is an apocalyptic number.

21660553061051 is a deficient number, since it is larger than the sum of its proper divisors (158854252549).

21660553061051 is a wasteful number, since it uses less digits than its factorization.

21660553061051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5420613.

The product of its (nonzero) digits is 162000, while the sum is 41.

Adding to 21660553061051 its reverse (15016035506612), we get a palindrome (36676588567663).

The spelling of 21660553061051 in words is "twenty-one trillion, six hundred sixty billion, five hundred fifty-three million, sixty-one thousand, fifty-one".