21626640842 has 16 divisors (see below), whose sum is σ = 32889757320. Its totient is φ = 10663437312.

The previous prime is 21626640839. The next prime is 21626640863. The reversal of 21626640842 is 24804662612.

It can be written as a sum of positive squares in 4 ways, for example, as 17476575601 + 4150065241 = 132199^2 + 64421^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21626640842.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1670948 + ... + 1683840.

Almost surely, 2^21626640842 is an apocalyptic number.

21626640842 is a deficient number, since it is larger than the sum of its proper divisors (11263116478).

21626640842 is a wasteful number, since it uses less digits than its factorization.

21626640842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24457.

The product of its (nonzero) digits is 221184, while the sum is 41.

The spelling of 21626640842 in words is "twenty-one billion, six hundred twenty-six million, six hundred forty thousand, eight hundred forty-two".