21512206354631 has 4 divisors (see below), whose sum is σ = 21512219424264. Its totient is φ = 21512193285000.

The previous prime is 21512206354607. The next prime is 21512206354633. The reversal of 21512206354631 is 13645360221512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21512206354631 - 2⁴² = 17114159843527 is a prime.

It is a super-2 number, since 2×21512206354631² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512206354633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3637745 + ... + 7500506.

It is an arithmetic number, because the mean of its divisors is an integer number (5378054856066).

Almost surely, 2^{21512206354631} is an apocalyptic number.

21512206354631 is a deficient number, since it is larger than the sum of its proper divisors (13069633).

21512206354631 is a wasteful number, since it uses less digits than its factorization.

21512206354631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13069632.

The product of its (nonzero) digits is 259200, while the sum is 41.

The spelling of 21512206354631 in words is "twenty-one trillion, five hundred twelve billion, two hundred six million, three hundred fifty-four thousand, six hundred thirty-one".