13409640 has 72 divisors (see below), whose sum is σ = 43808310. Its totient is φ = 3557376.

The previous prime is 13409633. The next prime is 13409647. The reversal of 13409640 is 4690431.

13409640 is a `hidden beast` number, since 13 + 4 + 0 + 9 + 640 = 666.

13409640 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (13409633) and next prime (13409647).

It can be written as a sum of positive squares in 3 ways, for example, as 7387524 + 6022116 = 2718^2 + 2454^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (13409647) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 69384 + ... + 69576.

Almost surely, 2^13409640 is an apocalyptic number.

13409640 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 13409640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21904155).

13409640 is an abundant number, since it is smaller than the sum of its proper divisors (30398670).

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

13409640 is a wasteful number, since it uses less digits than its factorization.

13409640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 13409640 is about 3661.9175304750. The cubic root of 13409640 is about 237.5777178710.

The spelling of 13409640 in words is "thirteen million, four hundred nine thousand, six hundred forty".