91801620 has 48 divisors (see below), whose sum is σ = 285606720. Its totient is φ = 24480288.

The previous prime is 91801609. The next prime is 91801621. The reversal of 91801620 is 2610819.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91801621) 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 15 ways as a sum of consecutive naturals, for example, 84462 + ... + 85541.

It is an arithmetic number, because the mean of its divisors is an integer number (5950140).

Almost surely, 2^91801620 is an apocalyptic number.

91801620 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

91801620 is an abundant number, since it is smaller than the sum of its proper divisors (193805100).

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

91801620 is a wasteful number, since it uses less digits than its factorization.

91801620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170021 (or 170013 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 91801620 is about 9581.3161935091. The cubic root of 91801620 is about 451.1110324246. Note that the first 3 decimals are identical.

The spelling of 91801620 in words is "ninety-one million, eight hundred one thousand, six hundred twenty".