91644618 has 64 divisors (see below), whose sum is σ = 205922304. Its totient is φ = 27000000.

The previous prime is 91644613. The next prime is 91644629. The reversal of 91644618 is 81644619.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (91644613) 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, 364993 + ... + 365243.

It is an arithmetic number, because the mean of its divisors is an integer number (3217536).

Almost surely, 2^91644618 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91644618, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102961152).

91644618 is an abundant number, since it is smaller than the sum of its proper divisors (114277686).

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

91644618 is a wasteful number, since it uses less digits than its factorization.

91644618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451.

The product of its digits is 41472, while the sum is 39.

The square root of 91644618 is about 9573.1195542519. The cubic root of 91644618 is about 450.8537176168.

Subtracting from 91644618 its reverse (81644619), we obtain a palindrome (9999999).

The spelling of 91644618 in words is "ninety-one million, six hundred forty-four thousand, six hundred eighteen".