21718220631 has 16 divisors (see below), whose sum is σ = 29048624640. Its totient is φ = 14433383520.

The previous prime is 21718220609. The next prime is 21718220651. The reversal of 21718220631 is 13602281712.

It is not a de Polignac number, because 21718220631 - 2⁹ = 21718220119 is a prime.

It is a super-2 number, since 2×21718220631² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21718220592 and 21718220601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21718220651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1378941 + ... + 1394601.

It is an arithmetic number, because the mean of its divisors is an integer number (1815539040).

Almost surely, 2^21718220631 is an apocalyptic number.

21718220631 is a deficient number, since it is larger than the sum of its proper divisors (7330404009).

21718220631 is a wasteful number, since it uses less digits than its factorization.

21718220631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17086.

The product of its (nonzero) digits is 8064, while the sum is 33.

The spelling of 21718220631 in words is "twenty-one billion, seven hundred eighteen million, two hundred twenty thousand, six hundred thirty-one".