78579154921 has 2 divisors, whose sum is σ = 78579154922. Its totient is φ = 78579154920.

The previous prime is 78579154909. The next prime is 78579154967. The reversal of 78579154921 is 12945197587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51858675625 + 26720479296 = 227725^2 + 163464^2 .

It is a cyclic number.

It is not a de Polignac number, because 78579154921 - 2⁵ = 78579154889 is a prime.

It is not a weakly prime, because it can be changed into another prime (78579154421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39289577460 + 39289577461.

It is an arithmetic number, because the mean of its divisors is an integer number (39289577461).

Almost surely, 2^78579154921 is an apocalyptic number.

It is an amenable number.

78579154921 is a deficient number, since it is larger than the sum of its proper divisors (1).

78579154921 is an equidigital number, since it uses as much as digits as its factorization.

78579154921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6350400, while the sum is 58.

The spelling of 78579154921 in words is "seventy-eight billion, five hundred seventy-nine million, one hundred fifty-four thousand, nine hundred twenty-one".