77794021 has 2 divisors, whose sum is σ = 77794022. Its totient is φ = 77794020.

The previous prime is 77793953. The next prime is 77794039. The reversal of 77794021 is 12049777.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77176225 + 617796 = 8785^2 + 786^2 .

It is a cyclic number.

It is not a de Polignac number, because 77794021 - 2⁹ = 77793509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77794081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38897010 + 38897011.

It is an arithmetic number, because the mean of its divisors is an integer number (38897011).

Almost surely, 2^77794021 is an apocalyptic number.

It is an amenable number.

77794021 is a deficient number, since it is larger than the sum of its proper divisors (1).

77794021 is an equidigital number, since it uses as much as digits as its factorization.

77794021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24696, while the sum is 37.

The square root of 77794021 is about 8820.0918929453. The cubic root of 77794021 is about 426.8894349255.

The spelling of 77794021 in words is "seventy-seven million, seven hundred ninety-four thousand, twenty-one".