21255354320631 has 8 divisors (see below), whose sum is σ = 28382583087600. Its totient is φ = 14149180883712.

The previous prime is 21255354320537. The next prime is 21255354320693. The reversal of 21255354320631 is 13602345355212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21255354320631 - 2¹⁰ = 21255354319607 is a prime.

It is a super-2 number, since 2×21255354320631² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255354320531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5263830156 + ... + 5263834193.

It is an arithmetic number, because the mean of its divisors is an integer number (3547822885950).

Almost surely, 2^{21255354320631} is an apocalyptic number.

21255354320631 is a deficient number, since it is larger than the sum of its proper divisors (7127228766969).

21255354320631 is a wasteful number, since it uses less digits than its factorization.

21255354320631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10527665025.

The product of its (nonzero) digits is 648000, while the sum is 42.

Adding to 21255354320631 its reverse (13602345355212), we get a palindrome (34857699675843).

The spelling of 21255354320631 in words is "twenty-one trillion, two hundred fifty-five billion, three hundred fifty-four million, three hundred twenty thousand, six hundred thirty-one".