90811840 has 112 divisors (see below), whose sum is σ = 251057664. Its totient is φ = 30643200.

The previous prime is 90811817. The next prime is 90811873. The reversal of 90811840 is 4811809.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158755 + ... + 159325.

Almost surely, 2^90811840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90811840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125528832).

90811840 is an abundant number, since it is smaller than the sum of its proper divisors (160245824).

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

90811840 is a wasteful number, since it uses less digits than its factorization.

90811840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666 (or 656 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 90811840 is about 9529.5246471165. The cubic root of 90811840 is about 449.4839186477.

Subtracting from 90811840 its sum of digits (31), we obtain a palindrome (90811809).

The spelling of 90811840 in words is "ninety million, eight hundred eleven thousand, eight hundred forty".