13805640 has 80 divisors (see below), whose sum is σ = 46413180. Its totient is φ = 3680640.

The previous prime is 13805629. The next prime is 13805641. The reversal of 13805640 is 4650831.

13805640 is a `hidden beast` number, since 13 + 8 + 0 + 5 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13089924 + 715716 = 3618^2 + 846^2 .

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

It is not an unprimeable number, because it can be changed into a prime (13805641) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1110 + ... + 5370.

Almost surely, 2^13805640 is an apocalyptic number.

13805640 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 13805640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23206590).

13805640 is an abundant number, since it is smaller than the sum of its proper divisors (32607540).

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

13805640 is a wasteful number, since it uses less digits than its factorization.

13805640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284 (or 4271 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 13805640 is about 3715.5941651370. The cubic root of 13805640 is about 239.8937029275.

The spelling of 13805640 in words is "thirteen million, eight hundred five thousand, six hundred forty".