78785191973 has 2 divisors, whose sum is σ = 78785191974. Its totient is φ = 78785191972.

The previous prime is 78785191889. The next prime is 78785192033. The reversal of 78785191973 is 37919158787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78785191969 + 4 = 280687^2 + 2^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78785191973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78785191073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39392595986 + 39392595987.

It is an arithmetic number, because the mean of its divisors is an integer number (39392595987).

Almost surely, 2^78785191973 is an apocalyptic number.

It is an amenable number.

78785191973 is a deficient number, since it is larger than the sum of its proper divisors (1).

78785191973 is an equidigital number, since it uses as much as digits as its factorization.

78785191973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26671680, while the sum is 65.

The spelling of 78785191973 in words is "seventy-eight billion, seven hundred eighty-five million, one hundred ninety-one thousand, nine hundred seventy-three".