91809900 has 432 divisors, whose sum is σ = 379142400. Its totient is φ = 18040320.

The previous prime is 91809863. The next prime is 91810007. The reversal of 91809900 is 990819.

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

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1556071 + ... + 1556129.

Almost surely, 2^91809900 is an apocalyptic number.

91809900 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91809900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189571200).

91809900 is an abundant number, since it is smaller than the sum of its proper divisors (287332500).

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

91809900 is a wasteful number, since it uses less digits than its factorization.

91809900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 91809900 is about 9581.7482747148. The cubic root of 91809900 is about 451.1245945929.

It can be divided in two parts, 91809 and 900, that multiplied together give a square (82628100 = 9090²).

The spelling of 91809900 in words is "ninety-one million, eight hundred nine thousand, nine hundred".