21530661124331 has 16 divisors (see below), whose sum is σ = 21881297055744. Its totient is φ = 21181578053184.

The previous prime is 21530661124327. The next prime is 21530661124337. The reversal of 21530661124331 is 13342116603512.

It is a cyclic number.

It is not a de Polignac number, because 21530661124331 - 2² = 21530661124327 is a prime.

It is a super-2 number, since 2×21530661124331² (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 (21530661124337) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65452790 + ... + 65780916.

It is an arithmetic number, because the mean of its divisors is an integer number (1367581065984).

Almost surely, 2^{21530661124331} is an apocalyptic number.

21530661124331 is a deficient number, since it is larger than the sum of its proper divisors (350635931413).

21530661124331 is a wasteful number, since it uses less digits than its factorization.

21530661124331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330490.

The product of its (nonzero) digits is 77760, while the sum is 38.

Adding to 21530661124331 its reverse (13342116603512), we get a palindrome (34872777727843).

The spelling of 21530661124331 in words is "twenty-one trillion, five hundred thirty billion, six hundred sixty-one million, one hundred twenty-four thousand, three hundred thirty-one".