91918990 has 8 divisors (see below), whose sum is σ = 165454200. Its totient is φ = 36767592.

The previous prime is 91918987. The next prime is 91919011. The reversal of 91918990 is 9981919.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 91918990.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4595940 + ... + 4595959.

It is an arithmetic number, because the mean of its divisors is an integer number (20681775).

Almost surely, 2^91918990 is an apocalyptic number.

91918990 is a deficient number, since it is larger than the sum of its proper divisors (73535210).

91918990 is a wasteful number, since it uses less digits than its factorization.

91918990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9191906.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 91918990 is about 9587.4391784251. The cubic root of 91918990 is about 451.3032017036.

It can be divided in two parts, 9191 and 8990, that added together give a palindrome (18181).

The spelling of 91918990 in words is "ninety-one million, nine hundred eighteen thousand, nine hundred ninety".