21530244164431 has 2 divisors, whose sum is σ = 21530244164432. Its totient is φ = 21530244164430.

The previous prime is 21530244164419. The next prime is 21530244164479. The reversal of 21530244164431 is 13446144203512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21530244164431 is a prime.

It is a super-2 number, since 2×21530244164431² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530244161431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765122082215 + 10765122082216.

It is an arithmetic number, because the mean of its divisors is an integer number (10765122082216).

Almost surely, 2^{21530244164431} is an apocalyptic number.

21530244164431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530244164431 is an equidigital number, since it uses as much as digits as its factorization.

21530244164431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 276480, while the sum is 40.

Adding to 21530244164431 its reverse (13446144203512), we get a palindrome (34976388367943).

The spelling of 21530244164431 in words is "twenty-one trillion, five hundred thirty billion, two hundred forty-four million, one hundred sixty-four thousand, four hundred thirty-one".