21056313630 has 32 divisors (see below), whose sum is σ = 55129258368. Its totient is φ = 5104560800.

The previous prime is 21056313599. The next prime is 21056313637. The reversal of 21056313630 is 3631365012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056313637) 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, 31903176 + ... + 31903835.

It is an arithmetic number, because the mean of its divisors is an integer number (1722789324).

Almost surely, 2^21056313630 is an apocalyptic number.

21056313630 is an abundant number, since it is smaller than the sum of its proper divisors (34072944738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21056313630 is a wasteful number, since it uses less digits than its factorization.

21056313630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63807032.

The product of its (nonzero) digits is 9720, while the sum is 30.

Adding to 21056313630 its reverse (3631365012), we get a palindrome (24687678642).

The spelling of 21056313630 in words is "twenty-one billion, fifty-six million, three hundred thirteen thousand, six hundred thirty".