91899818 has 4 divisors (see below), whose sum is σ = 137849730. Its totient is φ = 45949908.

The previous prime is 91899817. The next prime is 91899851. The reversal of 91899818 is 81899819.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 48958009 + 42941809 = 6997^2 + 6553^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 91899818.

It is not an unprimeable number, because it can be changed into a prime (91899817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22974953 + ... + 22974956.

Almost surely, 2^91899818 is an apocalyptic number.

91899818 is a deficient number, since it is larger than the sum of its proper divisors (45949912).

91899818 is a wasteful number, since it uses less digits than its factorization.

91899818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45949911.

The product of its digits is 373248, while the sum is 53.

The square root of 91899818 is about 9586.4392763945. The cubic root of 91899818 is about 451.2718226722.

Subtracting from 91899818 its reverse (81899819), we obtain a palindrome (9999999).

The spelling of 91899818 in words is "ninety-one million, eight hundred ninety-nine thousand, eight hundred eighteen".