21755800631 has 4 divisors (see below), whose sum is σ = 21812604672. Its totient is φ = 21698996592.

The previous prime is 21755800621. The next prime is 21755800657. The reversal of 21755800631 is 13600855712.

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 21755800631 - 2⁶ = 21755800567 is a prime.

It is a super-2 number, since 2×21755800631² (a number of 21 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 (21755800621) 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, 28401446 + ... + 28402211.

It is an arithmetic number, because the mean of its divisors is an integer number (5453151168).

Almost surely, 2^21755800631 is an apocalyptic number.

21755800631 is a deficient number, since it is larger than the sum of its proper divisors (56804041).

21755800631 is an equidigital number, since it uses as much as digits as its factorization.

21755800631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56804040.

The product of its (nonzero) digits is 50400, while the sum is 38.

The spelling of 21755800631 in words is "twenty-one billion, seven hundred fifty-five million, eight hundred thousand, six hundred thirty-one".