21390232516 has 9 divisors (see below), whose sum is σ = 37433418799. Its totient is φ = 10694970004.

The previous prime is 21390232477. The next prime is 21390232537. The reversal of 21390232516 is 61523209312.

The square root of 21390232516 is 146254.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 255945 + ... + 329071.

Almost surely, 2^21390232516 is an apocalyptic number.

21390232516 is the 146254-th square number.

It is an amenable number.

21390232516 is a deficient number, since it is larger than the sum of its proper divisors (16043186283).

21390232516 is an frugal number, since it uses more digits than its factorization.

21390232516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146258 (or 73129 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 34.

The spelling of 21390232516 in words is "twenty-one billion, three hundred ninety million, two hundred thirty-two thousand, five hundred sixteen".