91000900900 has 288 divisors, whose sum is σ = 264670560000. Its totient is φ = 26342184960.

The previous prime is 91000900897. The next prime is 91000900927. The reversal of 91000900900 is 900900019.

It is a super-2 number, since 2×91000900900² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

91000900900 is a modest number, since divided by 900900 gives 91000 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5005026 + ... + 5023174.

It is an arithmetic number, because the mean of its divisors is an integer number (918995000).

Almost surely, 2^91000900900 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 91000900900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132335280000).

91000900900 is an abundant number, since it is smaller than the sum of its proper divisors (173669659100).

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

91000900900 is a wasteful number, since it uses less digits than its factorization.

91000900900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18231 (or 18224 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 28.

The spelling of 91000900900 in words is "ninety-one billion, nine hundred thousand, nine hundred".