309513082921 has 81 divisors (see below), whose sum is σ = 392661319959. Its totient is φ = 243222509376.

The previous prime is 309513082919. The next prime is 309513082981. The reversal of 309513082921 is 129280315903.

The square root of 309513082921 is 556339.

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., 59433076521 + 250080006400 = 243789^2 + 500080^2 .

It is not a de Polignac number, because 309513082921 - 2¹ = 309513082919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (309513082981) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 3477675045 + ... + 3477675133.

Almost surely, 2^309513082921 is an apocalyptic number.

309513082921 is the 556339-th square number.

309513082921 is the 278170-th centered octagonal number.

It is an amenable number.

309513082921 is a deficient number, since it is larger than the sum of its proper divisors (83148237038).

309513082921 is an frugal number, since it uses more digits than its factorization.

309513082921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

The spelling of 309513082921 in words is "three hundred nine billion, five hundred thirteen million, eighty-two thousand, nine hundred twenty-one".