91691040 has 192 divisors, whose sum is σ = 341832960. Its totient is φ = 20213760.

The previous prime is 91691029. The next prime is 91691051. The reversal of 91691040 is 4019619.

It is an interprime number because it is at equal distance from previous prime (91691029) and next prime (91691051).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 91690989 and 91691007.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 96970 + ... + 97910.

It is an arithmetic number, because the mean of its divisors is an integer number (1780380).

Almost surely, 2^91691040 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 91691040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170916480).

91691040 is an abundant number, since it is smaller than the sum of its proper divisors (250141920).

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

91691040 is a wasteful number, since it uses less digits than its factorization.

91691040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995 (or 987 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 91691040 is about 9575.5438487848. The cubic root of 91691040 is about 450.9298304638.

The spelling of 91691040 in words is "ninety-one million, six hundred ninety-one thousand, forty".