21660536524643 has 2 divisors, whose sum is σ = 21660536524644. Its totient is φ = 21660536524642.

The previous prime is 21660536524619. The next prime is 21660536524699. The reversal of 21660536524643 is 34642563506612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21660536524643 - 2⁸ = 21660536524387 is a prime.

It is not a weakly prime, because it can be changed into another prime (21660535524643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830268262321 + 10830268262322.

It is an arithmetic number, because the mean of its divisors is an integer number (10830268262322).

Almost surely, 2^{21660536524643} is an apocalyptic number.

21660536524643 is a deficient number, since it is larger than the sum of its proper divisors (1).

21660536524643 is an equidigital number, since it uses as much as digits as its factorization.

21660536524643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18662400, while the sum is 53.

The spelling of 21660536524643 in words is "twenty-one trillion, six hundred sixty billion, five hundred thirty-six million, five hundred twenty-four thousand, six hundred forty-three".