77653921 has 2 divisors, whose sum is σ = 77653922. Its totient is φ = 77653920.

The previous prime is 77653843. The next prime is 77653963. The reversal of 77653921 is 12935677.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43560000 + 34093921 = 6600^2 + 5839^2 .

It is a cyclic number.

It is not a de Polignac number, because 77653921 - 2⁹ = 77653409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77653021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38826960 + 38826961.

It is an arithmetic number, because the mean of its divisors is an integer number (38826961).

Almost surely, 2^77653921 is an apocalyptic number.

It is an amenable number.

77653921 is a deficient number, since it is larger than the sum of its proper divisors (1).

77653921 is an equidigital number, since it uses as much as digits as its factorization.

77653921 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 77653921 is about 8812.1462198491. The cubic root of 77653921 is about 426.6330178406.

The spelling of 77653921 in words is "seventy-seven million, six hundred fifty-three thousand, nine hundred twenty-one".