21351630616 has 8 divisors (see below), whose sum is σ = 40034307420. Its totient is φ = 10675815304.

The previous prime is 21351630581. The next prime is 21351630617. The reversal of 21351630616 is 61603615312.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351630617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1334476906 + ... + 1334476921.

Almost surely, 2^21351630616 is an apocalyptic number.

It is an amenable number.

21351630616 is a deficient number, since it is larger than the sum of its proper divisors (18682676804).

21351630616 is a wasteful number, since it uses less digits than its factorization.

21351630616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2668953833 (or 2668953829 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 34.

The spelling of 21351630616 in words is "twenty-one billion, three hundred fifty-one million, six hundred thirty thousand, six hundred sixteen".