77393021 has 2 divisors, whose sum is σ = 77393022. Its totient is φ = 77393020.

The previous prime is 77393003. The next prime is 77393033. The reversal of 77393021 is 12039377.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52041796 + 25351225 = 7214^2 + 5035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77393021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77393051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38696510 + 38696511.

It is an arithmetic number, because the mean of its divisors is an integer number (38696511).

Almost surely, 2^77393021 is an apocalyptic number.

It is an amenable number.

77393021 is a deficient number, since it is larger than the sum of its proper divisors (1).

77393021 is an equidigital number, since it uses as much as digits as its factorization.

77393021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7938, while the sum is 32.

The square root of 77393021 is about 8797.3303336865. The cubic root of 77393021 is about 426.1546842141.

The spelling of 77393021 in words is "seventy-seven million, three hundred ninety-three thousand, twenty-one".