91421920 has 192 divisors, whose sum is σ = 253108800. Its totient is φ = 30965760.

The previous prime is 91421917. The next prime is 91421929. The reversal of 91421920 is 2912419.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91421929) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1498690 + ... + 1498750.

It is an arithmetic number, because the mean of its divisors is an integer number (1318275).

Almost surely, 2^91421920 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 91421920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126554400).

91421920 is an abundant number, since it is smaller than the sum of its proper divisors (161686880).

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

91421920 is a wasteful number, since it uses less digits than its factorization.

91421920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 91421920 is about 9561.4810568238. The cubic root of 91421920 is about 450.4882273081.

The spelling of 91421920 in words is "ninety-one million, four hundred twenty-one thousand, nine hundred twenty".