21777731269631 has 4 divisors (see below), whose sum is σ = 21779187307272. Its totient is φ = 21776275231992.

The previous prime is 21777731269627. The next prime is 21777731269709. The reversal of 21777731269631 is 13696213777712.

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 21777731269631 - 2² = 21777731269627 is a prime.

It is a super-2 number, since 2×21777731269631² (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 (21777731269531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 727996385 + ... + 728026298.

It is an arithmetic number, because the mean of its divisors is an integer number (5444796826818).

Almost surely, 2^{21777731269631} is an apocalyptic number.

21777731269631 is a deficient number, since it is larger than the sum of its proper divisors (1456037641).

21777731269631 is a wasteful number, since it uses less digits than its factorization.

21777731269631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1456037640.

The product of its digits is 28005264, while the sum is 62.

The spelling of 21777731269631 in words is "twenty-one trillion, seven hundred seventy-seven billion, seven hundred thirty-one million, two hundred sixty-nine thousand, six hundred thirty-one".