91999080 has 192 divisors, whose sum is σ = 320785920. Its totient is φ = 22809600.

The previous prime is 91999079. The next prime is 91999081. The reversal of 91999080 is 8099919.

91999080 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (91999079) and next prime (91999081).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (91999081) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 339345 + ... + 339615.

It is an arithmetic number, because the mean of its divisors is an integer number (1670760).

Almost surely, 2^91999080 is an apocalyptic number.

91999080 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 91999080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160392960).

91999080 is an abundant number, since it is smaller than the sum of its proper divisors (228786840).

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

91999080 is a wasteful number, since it uses less digits than its factorization.

91999080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 45.

The square root of 91999080 is about 9591.6150881903. The cubic root of 91999080 is about 451.4342387566.

It can be divided in two parts, 919 and 99080, that added together give a palindrome (99999).

The spelling of 91999080 in words is "ninety-one million, nine hundred ninety-nine thousand, eighty".