21390232515 has 16 divisors (see below), whose sum is σ = 34226244096. Its totient is φ = 11407500000.

The previous prime is 21390232477. The next prime is 21390232537. The reversal of 21390232515 is 51523209312.

It is a Cunningham number, because it is equal to 146254²-1.

It is not a de Polignac number, because 21390232515 - 2²⁰ = 21389183939 is a prime.

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, 414390 + ... + 463140.

It is an arithmetic number, because the mean of its divisors is an integer number (2139140256).

Almost surely, 2^21390232515 is an apocalyptic number.

21390232515 is a deficient number, since it is larger than the sum of its proper divisors (12836011581).

21390232515 is a wasteful number, since it uses less digits than its factorization.

21390232515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78010.

The product of its (nonzero) digits is 16200, while the sum is 33.

The spelling of 21390232515 in words is "twenty-one billion, three hundred ninety million, two hundred thirty-two thousand, five hundred fifteen".