91780920 has 432 divisors, whose sum is σ = 390269880. Its totient is φ = 18627840.

The previous prime is 91780891. The next prime is 91780933. The reversal of 91780920 is 2908719.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 2134419 + ... + 2134461.

Almost surely, 2^91780920 is an apocalyptic number.

91780920 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 91780920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195134940).

91780920 is an abundant number, since it is smaller than the sum of its proper divisors (298488960).

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

91780920 is a wasteful number, since it uses less digits than its factorization.

91780920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 91780920 is about 9580.2359052374. The cubic root of 91780920 is about 451.0771234357.

The spelling of 91780920 in words is "ninety-one million, seven hundred eighty thousand, nine hundred twenty".