78790406561 has 2 divisors, whose sum is σ = 78790406562. Its totient is φ = 78790406560.

The previous prime is 78790406543. The next prime is 78790406567. The reversal of 78790406561 is 16560409787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77320144225 + 1470262336 = 278065^2 + 38344^2 .

It is a cyclic number.

It is not a de Polignac number, because 78790406561 - 2¹⁸ = 78790144417 is a prime.

It is not a weakly prime, because it can be changed into another prime (78790406567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39395203280 + 39395203281.

It is an arithmetic number, because the mean of its divisors is an integer number (39395203281).

Almost surely, 2^78790406561 is an apocalyptic number.

It is an amenable number.

78790406561 is a deficient number, since it is larger than the sum of its proper divisors (1).

78790406561 is an equidigital number, since it uses as much as digits as its factorization.

78790406561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2540160, while the sum is 53.

The spelling of 78790406561 in words is "seventy-eight billion, seven hundred ninety million, four hundred six thousand, five hundred sixty-one".