78000091 has 10 divisors (see below), whose sum is σ = 84530812. Its totient is φ = 71973720.

The previous prime is 78000089. The next prime is 78000101. The reversal of 78000091 is 19000087.

It is not a de Polignac number, because 78000091 - 2¹ = 78000089 is a prime.

It is a Duffinian number.

78000091 is a modest number, since divided by 91 gives 78 as remainder.

It is not an unprimeable number, because it can be changed into a prime (78000001) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 27196 + ... + 29926.

Almost surely, 2^78000091 is an apocalyptic number.

78000091 is a deficient number, since it is larger than the sum of its proper divisors (6530721).

78000091 is an frugal number, since it uses more digits than its factorization.

78000091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2783 (or 2744 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 78000091 is about 8831.7660181868. The cubic root of 78000091 is about 427.2660343287.

The spelling of 78000091 in words is "seventy-eight million, ninety-one", and thus it is an aban number and an uban number.