77609531 has 2 divisors, whose sum is σ = 77609532. Its totient is φ = 77609530.

The previous prime is 77609501. The next prime is 77609533. The reversal of 77609531 is 13590677.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77609531 is a prime.

It is a super-2 number, since 2×77609531² = 12046478604079922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 77609533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77609533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38804765 + 38804766.

It is an arithmetic number, because the mean of its divisors is an integer number (38804766).

Almost surely, 2^77609531 is an apocalyptic number.

77609531 is a deficient number, since it is larger than the sum of its proper divisors (1).

77609531 is an equidigital number, since it uses as much as digits as its factorization.

77609531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39690, while the sum is 38.

The square root of 77609531 is about 8809.6271771284. The cubic root of 77609531 is about 426.5517090062.

The spelling of 77609531 in words is "seventy-seven million, six hundred nine thousand, five hundred thirty-one".