78439087997 has 2 divisors, whose sum is σ = 78439087998. Its totient is φ = 78439087996.

The previous prime is 78439087957. The next prime is 78439088003. The reversal of 78439087997 is 79978093487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41657218201 + 36781869796 = 204101^2 + 191786^2 .

It is a cyclic number.

It is not a de Polignac number, because 78439087997 - 2²⁸ = 78170652541 is a prime.

It is a super-2 number, since 2×78439087997² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78439087997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78439087957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39219543998 + 39219543999.

It is an arithmetic number, because the mean of its divisors is an integer number (39219543999).

Almost surely, 2^78439087997 is an apocalyptic number.

It is an amenable number.

78439087997 is a deficient number, since it is larger than the sum of its proper divisors (1).

78439087997 is an equidigital number, since it uses as much as digits as its factorization.

78439087997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192036096, while the sum is 71.

The spelling of 78439087997 in words is "seventy-eight billion, four hundred thirty-nine million, eighty-seven thousand, nine hundred ninety-seven".