21720726712 has 16 divisors (see below), whose sum is σ = 40933098360. Its totient is φ = 10805233824.

The previous prime is 21720726647. The next prime is 21720726737. The reversal of 21720726712 is 21762702712.

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, 6889518 + ... + 6892669.

Almost surely, 2^21720726712 is an apocalyptic number.

It is an amenable number.

21720726712 is a deficient number, since it is larger than the sum of its proper divisors (19212371648).

21720726712 is a wasteful number, since it uses less digits than its factorization.

21720726712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13782390 (or 13782386 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 37.

The spelling of 21720726712 in words is "twenty-one billion, seven hundred twenty million, seven hundred twenty-six thousand, seven hundred twelve".