77708639 has 2 divisors, whose sum is σ = 77708640. Its totient is φ = 77708638.

The previous prime is 77708627. The next prime is 77708647. The reversal of 77708639 is 93680777.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77708639 - 2⁴ = 77708623 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 77708593 and 77708602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77708669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38854319 + 38854320.

It is an arithmetic number, because the mean of its divisors is an integer number (38854320).

Almost surely, 2^77708639 is an apocalyptic number.

77708639 is a deficient number, since it is larger than the sum of its proper divisors (1).

77708639 is an equidigital number, since it uses as much as digits as its factorization.

77708639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 444528, while the sum is 47.

The square root of 77708639 is about 8815.2503651343. The cubic root of 77708639 is about 426.7332017685.

The spelling of 77708639 in words is "seventy-seven million, seven hundred eight thousand, six hundred thirty-nine".