21679952540 has 12 divisors (see below), whose sum is σ = 45527900376. Its totient is φ = 8671981008.

The previous prime is 21679952509. The next prime is 21679952561. The reversal of 21679952540 is 4525997612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 541998794 + ... + 541998833.

It is an arithmetic number, because the mean of its divisors is an integer number (3793991698).

Almost surely, 2^21679952540 is an apocalyptic number.

21679952540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21679952540 is an abundant number, since it is smaller than the sum of its proper divisors (23847947836).

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

21679952540 is a wasteful number, since it uses less digits than its factorization.

21679952540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083997636 (or 1083997634 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 50.

The spelling of 21679952540 in words is "twenty-one billion, six hundred seventy-nine million, nine hundred fifty-two thousand, five hundred forty".