77312569 has 2 divisors, whose sum is σ = 77312570. Its totient is φ = 77312568.

The previous prime is 77312567. The next prime is 77312629. The reversal of 77312569 is 96521377.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64208169 + 13104400 = 8013^2 + 3620^2 .

It is a cyclic number.

It is not a de Polignac number, because 77312569 - 2¹ = 77312567 is a prime.

It is a super-2 number, since 2×77312569² = 11954466650759522, which contains 22 as substring.

Together with 77312567, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (77312561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38656284 + 38656285.

It is an arithmetic number, because the mean of its divisors is an integer number (38656285).

Almost surely, 2^77312569 is an apocalyptic number.

It is an amenable number.

77312569 is a deficient number, since it is larger than the sum of its proper divisors (1).

77312569 is an equidigital number, since it uses as much as digits as its factorization.

77312569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 79380, while the sum is 40.

The square root of 77312569 is about 8792.7566212195. The cubic root of 77312569 is about 426.0069668312.

The spelling of 77312569 in words is "seventy-seven million, three hundred twelve thousand, five hundred sixty-nine".