77692721 has 2 divisors, whose sum is σ = 77692722. Its totient is φ = 77692720.

The previous prime is 77692717. The next prime is 77692723. The reversal of 77692721 is 12729677.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74218225 + 3474496 = 8615^2 + 1864^2 .

It is a cyclic number.

It is not a de Polignac number, because 77692721 - 2² = 77692717 is a prime.

Together with 77692723, 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 (77692723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38846360 + 38846361.

It is an arithmetic number, because the mean of its divisors is an integer number (38846361).

Almost surely, 2^77692721 is an apocalyptic number.

It is an amenable number.

77692721 is a deficient number, since it is larger than the sum of its proper divisors (1).

77692721 is an equidigital number, since it uses as much as digits as its factorization.

77692721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 74088, while the sum is 41.

The square root of 77692721 is about 8814.3474517403. The cubic root of 77692721 is about 426.7040621385.

The spelling of 77692721 in words is "seventy-seven million, six hundred ninety-two thousand, seven hundred twenty-one".