91990080 has 504 divisors, whose sum is σ = 406066752. Its totient is φ = 19408896.

The previous prime is 91990007. The next prime is 91990081. The reversal of 91990080 is 8009919.

It is a tau number, because it is divible by the number of its divisors (504).

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

It is not an unprimeable number, because it can be changed into a prime (91990081) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 7076154 + ... + 7076166.

It is an arithmetic number, because the mean of its divisors is an integer number (805688).

Almost surely, 2^91990080 is an apocalyptic number.

91990080 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 91990080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203033376).

91990080 is an abundant number, since it is smaller than the sum of its proper divisors (314076672).

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

91990080 is a wasteful number, since it uses less digits than its factorization.

91990080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 30 counting only the distinct ones).

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

The square root of 91990080 is about 9591.1459169382. The cubic root of 91990080 is about 451.4195174476.

Adding to 91990080 its reverse (8009919), we get a palindrome (99999999).

The spelling of 91990080 in words is "ninety-one million, nine hundred ninety thousand, eighty".