77923548721 has 2 divisors, whose sum is σ = 77923548722. Its totient is φ = 77923548720.

The previous prime is 77923548697. The next prime is 77923548739. The reversal of 77923548721 is 12784532977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77415271696 + 508277025 = 278236^2 + 22545^2 .

It is a cyclic number.

It is not a de Polignac number, because 77923548721 - 2¹⁹ = 77923024433 is a prime.

It is not a weakly prime, because it can be changed into another prime (77923548421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38961774360 + 38961774361.

It is an arithmetic number, because the mean of its divisors is an integer number (38961774361).

Almost surely, 2^77923548721 is an apocalyptic number.

It is an amenable number.

77923548721 is a deficient number, since it is larger than the sum of its proper divisors (1).

77923548721 is an equidigital number, since it uses as much as digits as its factorization.

77923548721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5927040, while the sum is 55.

The spelling of 77923548721 in words is "seventy-seven billion, nine hundred twenty-three million, five hundred forty-eight thousand, seven hundred twenty-one".