91200080 has 40 divisors (see below), whose sum is σ = 214439400. Its totient is φ = 36067328.

The previous prime is 91200077. The next prime is 91200089. The reversal of 91200080 is 8000219.

It can be written as a sum of positive squares in 4 ways, for example, as 341056 + 90859024 = 584^2 + 9532^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91200089) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 716 + ... + 13524.

It is an arithmetic number, because the mean of its divisors is an integer number (5360985).

Almost surely, 2^91200080 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 91200080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107219700).

91200080 is an abundant number, since it is smaller than the sum of its proper divisors (123239320).

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

91200080 is a wasteful number, since it uses less digits than its factorization.

91200080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12911 (or 12905 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 91200080 is about 9549.8732975888. The cubic root of 91200080 is about 450.1235545504.

Adding to 91200080 its reverse (8000219), we get a palindrome (99200299).

The spelling of 91200080 in words is "ninety-one million, two hundred thousand, eighty".