91891072 has 160 divisors (see below), whose sum is σ = 239989680. Its totient is φ = 34771968.

The previous prime is 91891067. The next prime is 91891073. The reversal of 91891072 is 27019819.

It is a super-2 number, since 2×91891072² = 16887938226618368, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91891073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3995253 + ... + 3995275.

Almost surely, 2^91891072 is an apocalyptic number.

91891072 is a gapful number since it is divisible by the number (92) 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 91891072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119994840).

91891072 is an abundant number, since it is smaller than the sum of its proper divisors (148098608).

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

91891072 is an equidigital number, since it uses as much as digits as its factorization.

91891072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78 (or 45 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 91891072 is about 9585.9831003398. The cubic root of 91891072 is about 451.2575065446.

The spelling of 91891072 in words is "ninety-one million, eight hundred ninety-one thousand, seventy-two".