21318606356 has 36 divisors (see below), whose sum is σ = 39649978368. Its totient is φ = 10027536768.

The previous prime is 21318606341. The next prime is 21318606371. The reversal of 21318606356 is 65360681312.

It is an interprime number because it is at equal distance from previous prime (21318606341) and next prime (21318606371).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4139375 + ... + 4144521.

It is an arithmetic number, because the mean of its divisors is an integer number (1101388288).

Almost surely, 2^21318606356 is an apocalyptic number.

It is an amenable number.

21318606356 is a deficient number, since it is larger than the sum of its proper divisors (18331372012).

21318606356 is a wasteful number, since it uses less digits than its factorization.

21318606356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8768 (or 8749 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 21318606356 in words is "twenty-one billion, three hundred eighteen million, six hundred six thousand, three hundred fifty-six".