79678639 has 2 divisors, whose sum is σ = 79678640. Its totient is φ = 79678638.

The previous prime is 79678633. The next prime is 79678679. The reversal of 79678639 is 93687697.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 79678639 - 2¹³ = 79670447 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 79678639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79678633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39839319 + 39839320.

It is an arithmetic number, because the mean of its divisors is an integer number (39839320).

Almost surely, 2^79678639 is an apocalyptic number.

79678639 is a deficient number, since it is larger than the sum of its proper divisors (1).

79678639 is an equidigital number, since it uses as much as digits as its factorization.

79678639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3429216, while the sum is 55.

The square root of 79678639 is about 8926.2892066076. The cubic root of 79678639 is about 430.3092043213.

The spelling of 79678639 in words is "seventy-nine million, six hundred seventy-eight thousand, six hundred thirty-nine".