21639854894 has 32 divisors (see below), whose sum is σ = 37303343616. Its totient is φ = 9222685920.

The previous prime is 21639854881. The next prime is 21639854917. The reversal of 21639854894 is 49845893612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4998959 + ... + 5003285.

It is an arithmetic number, because the mean of its divisors is an integer number (1165729488).

Almost surely, 2^21639854894 is an apocalyptic number.

21639854894 is a deficient number, since it is larger than the sum of its proper divisors (15663488722).

21639854894 is a wasteful number, since it uses less digits than its factorization.

21639854894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6240.

The product of its digits is 14929920, while the sum is 59.

The spelling of 21639854894 in words is "twenty-one billion, six hundred thirty-nine million, eight hundred fifty-four thousand, eight hundred ninety-four".