21566097316 has 27 divisors (see below), whose sum is σ = 38170544097. Its totient is φ = 10661600400.

The previous prime is 21566097271. The next prime is 21566097379. The reversal of 21566097316 is 61379066512.

The square root of 21566097316 is 146854.

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

It can be written as a sum of positive squares in only one way, i.e., 20720450916 + 845646400 = 143946^2 + 29080^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 29664145 + ... + 29664871.

Almost surely, 2^21566097316 is an apocalyptic number.

21566097316 is the 146854-th square number.

It is an amenable number.

21566097316 is a deficient number, since it is larger than the sum of its proper divisors (16604446781).

21566097316 is an frugal number, since it uses more digits than its factorization.

21566097316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1660 (or 830 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 46.

The spelling of 21566097316 in words is "twenty-one billion, five hundred sixty-six million, ninety-seven thousand, three hundred sixteen".