91999023 has 8 divisors (see below), whose sum is σ = 122776368. Its totient is φ = 61277184.

The previous prime is 91999021. The next prime is 91999027. The reversal of 91999023 is 32099919.

It is a happy number.

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

It is not a de Polignac number, because 91999023 - 2¹ = 91999021 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91999021) 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, 9840 + ... + 16757.

It is an arithmetic number, because the mean of its divisors is an integer number (15347046).

Almost surely, 2^91999023 is an apocalyptic number.

91999023 is a deficient number, since it is larger than the sum of its proper divisors (30777345).

91999023 is a wasteful number, since it uses less digits than its factorization.

91999023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27753.

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 91999023 is about 9591.6121168446. The cubic root of 91999023 is about 451.4341455246.

It can be divided in two parts, 9199902 and 3, that added together give a triangular number (9199905 = T₄₂₈₉).

The spelling of 91999023 in words is "ninety-one million, nine hundred ninety-nine thousand, twenty-three".