90191808 has 84 divisors (see below), whose sum is σ = 295462960. Its totient is φ = 25767936.

The previous prime is 90191807. The next prime is 90191831. The reversal of 90191808 is 80819109.

It is a tau number, because it is divible by the number of its divisors (84).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90191807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7153 + ... + 15216.

Almost surely, 2^90191808 is an apocalyptic number.

It is an amenable number.

90191808 is an abundant number, since it is smaller than the sum of its proper divisors (205271152).

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

90191808 is a wasteful number, since it uses less digits than its factorization.

90191808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22394 (or 22381 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 90191808 is about 9496.9367692957. The cubic root of 90191808 is about 448.4586077541.

The spelling of 90191808 in words is "ninety million, one hundred ninety-one thousand, eight hundred eight".