21710221515 has 12 divisors (see below), whose sum is σ = 37631050704. Its totient is φ = 11578784784.

The previous prime is 21710221397. The next prime is 21710221567. The reversal of 21710221515 is 51512201712.

21710221515 is a `hidden beast` number, since 21 + 7 + 102 + 21 + 515 = 666.

It is not a de Polignac number, because 21710221515 - 2⁹ = 21710221003 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241224639 + ... + 241224728.

It is an arithmetic number, because the mean of its divisors is an integer number (3135920892).

Almost surely, 2^21710221515 is an apocalyptic number.

21710221515 is a deficient number, since it is larger than the sum of its proper divisors (15920829189).

21710221515 is a wasteful number, since it uses less digits than its factorization.

21710221515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482449378 (or 482449375 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 27.

The spelling of 21710221515 in words is "twenty-one billion, seven hundred ten million, two hundred twenty-one thousand, five hundred fifteen".