13643640 has 80 divisors (see below), whose sum is σ = 45868680. Its totient is φ = 3637440.

The previous prime is 13643633. The next prime is 13643683. The reversal of 13643640 is 4634631.

13643640 is a `hidden beast` number, since 13 + 6 + 4 + 3 + 640 = 666.

13643640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×13643640² = 372297824899200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1135 + ... + 5345.

Almost surely, 2^13643640 is an apocalyptic number.

13643640 is a gapful number since it is divisible by the number (10) 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 13643640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22934340).

13643640 is an abundant number, since it is smaller than the sum of its proper divisors (32225040).

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

13643640 is a wasteful number, since it uses less digits than its factorization.

13643640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4234 (or 4221 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 13643640 is about 3693.7298222799. The cubic root of 13643640 is about 238.9516775843.

Subtracting from 13643640 its reverse (4634631), we obtain a palindrome (9009009).

The spelling of 13643640 in words is "thirteen million, six hundred forty-three thousand, six hundred forty".