78739769 has 2 divisors, whose sum is σ = 78739770. Its totient is φ = 78739768.

The previous prime is 78739763. The next prime is 78739823. The reversal of 78739769 is 96793787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54582544 + 24157225 = 7388^2 + 4915^2 .

It is a cyclic number.

It is not a de Polignac number, because 78739769 - 2⁴ = 78739753 is a prime.

It is a super-2 number, since 2×78739769² = 12399902444346722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78739763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39369884 + 39369885.

It is an arithmetic number, because the mean of its divisors is an integer number (39369885).

Almost surely, 2^78739769 is an apocalyptic number.

It is an amenable number.

78739769 is a deficient number, since it is larger than the sum of its proper divisors (1).

78739769 is an equidigital number, since it uses as much as digits as its factorization.

78739769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4000752, while the sum is 56.

The square root of 78739769 is about 8873.5432043801. The cubic root of 78739769 is about 428.6123810972.

The spelling of 78739769 in words is "seventy-eight million, seven hundred thirty-nine thousand, seven hundred sixty-nine".