21213600655631 has 2 divisors, whose sum is σ = 21213600655632. Its totient is φ = 21213600655630.

The previous prime is 21213600655531. The next prime is 21213600655669. The reversal of 21213600655631 is 13655600631212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213600655631 is a prime.

It is a super-2 number, since 2×21213600655631² (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 (21213600655531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606800327815 + 10606800327816.

It is an arithmetic number, because the mean of its divisors is an integer number (10606800327816).

Almost surely, 2^{21213600655631} is an apocalyptic number.

21213600655631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213600655631 is an equidigital number, since it uses as much as digits as its factorization.

21213600655631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 41.

The spelling of 21213600655631 in words is "twenty-one trillion, two hundred thirteen billion, six hundred million, six hundred fifty-five thousand, six hundred thirty-one".