91189980 has 180 divisors, whose sum is σ = 324221352. Its totient is φ = 20744640.

The previous prime is 91189979. The next prime is 91189981. The reversal of 91189980 is 8998119.

It is an interprime number because it is at equal distance from previous prime (91189979) and next prime (91189981).

It is a tau number, because it is divible by the number of its divisors (180).

It is a super-2 number, since 2×91189980² = 16631224904800800, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91189981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 432075 + ... + 432285.

Almost surely, 2^91189980 is an apocalyptic number.

91189980 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 91189980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162110676).

91189980 is an abundant number, since it is smaller than the sum of its proper divisors (233031372).

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

91189980 is a wasteful number, since it uses less digits than its factorization.

91189980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254 (or 228 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 91189980 is about 9549.3444801201. The cubic root of 91189980 is about 450.1069375484.

The spelling of 91189980 in words is "ninety-one million, one hundred eighty-nine thousand, nine hundred eighty".