91981236 has 24 divisors (see below), whose sum is σ = 218262240. Its totient is φ = 30140512.

The previous prime is 91981231. The next prime is 91981249. The reversal of 91981236 is 63218919.

It is a junction number, because it is equal to n+sod(n) for n = 91981194 and 91981203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91981231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64251 + ... + 65666.

It is an arithmetic number, because the mean of its divisors is an integer number (9094260).

Almost surely, 2^91981236 is an apocalyptic number.

It is an amenable number.

91981236 is an abundant number, since it is smaller than the sum of its proper divisors (126281004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91981236 is a wasteful number, since it uses less digits than its factorization.

91981236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129983 (or 129981 counting only the distinct ones).

The product of its digits is 23328, while the sum is 39.

The square root of 91981236 is about 9590.6848556294. The cubic root of 91981236 is about 451.4050503726.

The spelling of 91981236 in words is "ninety-one million, nine hundred eighty-one thousand, two hundred thirty-six".