78993691 has 16 divisors (see below), whose sum is σ = 92664000. Its totient is φ = 65939328.

The previous prime is 78993683. The next prime is 78993727. The reversal of 78993691 is 19639987.

It is not a de Polignac number, because 78993691 - 2³ = 78993683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78993091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54565 + ... + 55993.

It is an arithmetic number, because the mean of its divisors is an integer number (5791500).

Almost surely, 2^78993691 is an apocalyptic number.

78993691 is a deficient number, since it is larger than the sum of its proper divisors (13670309).

78993691 is a wasteful number, since it uses less digits than its factorization.

78993691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1638.

The product of its digits is 734832, while the sum is 52.

The square root of 78993691 is about 8887.8395012511. The cubic root of 78993691 is about 429.0726200727.

The spelling of 78993691 in words is "seventy-eight million, nine hundred ninety-three thousand, six hundred ninety-one".