13640720 has 20 divisors (see below), whose sum is σ = 31714860. Its totient is φ = 5456256.

The previous prime is 13640699. The next prime is 13640723. The reversal of 13640720 is 2704631.

It can be written as a sum of positive squares in 2 ways, for example, as 8202496 + 5438224 = 2864^2 + 2332^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (13640723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85175 + ... + 85334.

It is an arithmetic number, because the mean of its divisors is an integer number (1585743).

Almost surely, 2^13640720 is an apocalyptic number.

13640720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13640720 is an abundant number, since it is smaller than the sum of its proper divisors (18074140).

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

13640720 is a wasteful number, since it uses less digits than its factorization.

13640720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170522 (or 170516 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 13640720 is about 3693.3345367026. The cubic root of 13640720 is about 238.9346296244.

The spelling of 13640720 in words is "thirteen million, six hundred forty thousand, seven hundred twenty".