21612572352991 has 2 divisors, whose sum is σ = 21612572352992. Its totient is φ = 21612572352990.

The previous prime is 21612572352961. The next prime is 21612572353037. The reversal of 21612572352991 is 19925327521612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21612572352991 - 2⁴³ = 12816479330783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21612572352941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10806286176495 + 10806286176496.

It is an arithmetic number, because the mean of its divisors is an integer number (10806286176496).

Almost surely, 2^{21612572352991} is an apocalyptic number.

21612572352991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21612572352991 is an equidigital number, since it uses as much as digits as its factorization.

21612572352991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4082400, while the sum is 55.

The spelling of 21612572352991 in words is "twenty-one trillion, six hundred twelve billion, five hundred seventy-two million, three hundred fifty-two thousand, nine hundred ninety-one".