91664540 has 48 divisors (see below), whose sum is σ = 215689824. Its totient is φ = 32428800.

The previous prime is 91664497. The next prime is 91664543. The reversal of 91664540 is 4546619.

It is a self number, because there is not a number n which added to its sum of digits gives 91664540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91664543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2510 + ... + 13770.

It is an arithmetic number, because the mean of its divisors is an integer number (4493538).

Almost surely, 2^91664540 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 91664540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107844912).

91664540 is an abundant number, since it is smaller than the sum of its proper divisors (124025284).

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

91664540 is a wasteful number, since it uses less digits than its factorization.

91664540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11318 (or 11316 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 91664540 is about 9574.1600153747. The cubic root of 91664540 is about 450.8863845906.

It can be divided in two parts, 916 and 64540, that added together give a palindrome (65456).

The spelling of 91664540 in words is "ninety-one million, six hundred sixty-four thousand, five hundred forty".