78638091 has 24 divisors (see below), whose sum is σ = 124050240. Its totient is φ = 44169552.

The previous prime is 78638057. The next prime is 78638117. The reversal of 78638091 is 19083687.

It is not a de Polignac number, because 78638091 - 2⁷ = 78637963 is a prime.

It is a super-2 number, since 2×78638091² = 12367898712248562, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78638011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4140 + ... + 13206.

It is an arithmetic number, because the mean of its divisors is an integer number (5168760).

Almost surely, 2^78638091 is an apocalyptic number.

78638091 is a deficient number, since it is larger than the sum of its proper divisors (45412149).

78638091 is a wasteful number, since it uses less digits than its factorization.

78638091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9143 (or 9136 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 78638091 is about 8867.8120751401. The cubic root of 78638091 is about 428.4278101473.

The spelling of 78638091 in words is "seventy-eight million, six hundred thirty-eight thousand, ninety-one".