21206711115 has 64 divisors (see below), whose sum is σ = 39977884800. Its totient is φ = 10629107712.

The previous prime is 21206711087. The next prime is 21206711143. The reversal of 21206711115 is 51111760212.

It is an interprime number because it is at equal distance from previous prime (21206711087) and next prime (21206711143).

It is not a de Polignac number, because 21206711115 - 2⁵ = 21206711083 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1620639 + ... + 1633671.

It is an arithmetic number, because the mean of its divisors is an integer number (624654450).

Almost surely, 2^21206711115 is an apocalyptic number.

21206711115 is a deficient number, since it is larger than the sum of its proper divisors (18771173685).

21206711115 is a wasteful number, since it uses less digits than its factorization.

21206711115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13773 (or 13767 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 27.

The spelling of 21206711115 in words is "twenty-one billion, two hundred six million, seven hundred eleven thousand, one hundred fifteen".