77912321 has 2 divisors, whose sum is σ = 77912322. Its totient is φ = 77912320.

The previous prime is 77912297. The next prime is 77912449. The reversal of 77912321 is 12321977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67831696 + 10080625 = 8236^2 + 3175^2 .

It is an emirp because it is prime and its reverse (12321977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77912321 - 2¹⁰ = 77911297 is a prime.

It is not a weakly prime, because it can be changed into another prime (77912221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38956160 + 38956161.

It is an arithmetic number, because the mean of its divisors is an integer number (38956161).

Almost surely, 2^77912321 is an apocalyptic number.

It is an amenable number.

77912321 is a deficient number, since it is larger than the sum of its proper divisors (1).

77912321 is an equidigital number, since it uses as much as digits as its factorization.

77912321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5292, while the sum is 32.

The square root of 77912321 is about 8826.7956246874. The cubic root of 77912321 is about 427.1057130852.

The spelling of 77912321 in words is "seventy-seven million, nine hundred twelve thousand, three hundred twenty-one".