309657747961 has 9 divisors (see below), whose sum is σ = 311082692493. Its totient is φ = 308239308480.

The previous prime is 309657747943. The next prime is 309657747979. The reversal of 309657747961 is 169747756903.

The square root of 309657747961 is 556469.

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

It is an interprime number because it is at equal distance from previous prime (309657747943) and next prime (309657747979).

It can be written as a sum of positive squares in 4 ways, for example, as 107571536361 + 202086211600 = 327981^2 + 449540^2 .

It is not a de Polignac number, because 309657747961 - 2⁵ = 309657747929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 309657747893 and 309657747902.

It is not an unprimeable number, because it can be changed into a prime (309657747361) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 134107875 + ... + 134110183.

Almost surely, 2^309657747961 is an apocalyptic number.

309657747961 is the 556469-th square number.

309657747961 is the 278235-th centered octagonal number.

It is an amenable number.

309657747961 is a deficient number, since it is larger than the sum of its proper divisors (1424944532).

309657747961 is an frugal number, since it uses more digits than its factorization.

309657747961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5100 (or 2550 counting only the distinct ones).

The product of its (nonzero) digits is 60011280, while the sum is 64.

Multiplying 309657747961 by its sum of digits (64), we get a square (19818095869504 = 4451752²).

The spelling of 309657747961 in words is "three hundred nine billion, six hundred fifty-seven million, seven hundred forty-seven thousand, nine hundred sixty-one".