91333981 has 4 divisors (see below), whose sum is σ = 91991200. Its totient is φ = 90676764.

The previous prime is 91333973. The next prime is 91334003. The reversal of 91333981 is 18933319.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91333981 - 2³ = 91333973 is a prime.

It is a super-2 number, since 2×91333981² = 16683792170616722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91333981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91333901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 328401 + ... + 328678.

It is an arithmetic number, because the mean of its divisors is an integer number (22997800).

Almost surely, 2^91333981 is an apocalyptic number.

It is an amenable number.

91333981 is a deficient number, since it is larger than the sum of its proper divisors (657219).

91333981 is a wasteful number, since it uses less digits than its factorization.

91333981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657218.

The product of its digits is 17496, while the sum is 37.

The square root of 91333981 is about 9556.8813427812. The cubic root of 91333981 is about 450.3437390092.

The spelling of 91333981 in words is "ninety-one million, three hundred thirty-three thousand, nine hundred eighty-one".