78694939 has 2 divisors, whose sum is σ = 78694940. Its totient is φ = 78694938.

The previous prime is 78694927. The next prime is 78695003. The reversal of 78694939 is 93949687.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78694939 - 2¹¹ = 78692891 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78694939.

It is not a weakly prime, because it can be changed into another prime (78694039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39347469 + 39347470.

It is an arithmetic number, because the mean of its divisors is an integer number (39347470).

Almost surely, 2^78694939 is an apocalyptic number.

78694939 is a deficient number, since it is larger than the sum of its proper divisors (1).

78694939 is an equidigital number, since it uses as much as digits as its factorization.

78694939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 55.

The square root of 78694939 is about 8871.0167962867. The cubic root of 78694939 is about 428.5310230531.

The spelling of 78694939 in words is "seventy-eight million, six hundred ninety-four thousand, nine hundred thirty-nine".