13720640 has 56 divisors (see below), whose sum is σ = 33329880. Its totient is φ = 5378048.

The previous prime is 13720639. The next prime is 13720657. The reversal of 13720640 is 4602731.

It can be written as a sum of positive squares in 4 ways, for example, as 5053504 + 8667136 = 2248^2 + 2944^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16556 + ... + 17364.

Almost surely, 2^13720640 is an apocalyptic number.

13720640 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 13720640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16664940).

13720640 is an abundant number, since it is smaller than the sum of its proper divisors (19609240).

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

13720640 is an equidigital number, since it uses as much as digits as its factorization.

13720640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879 (or 869 counting only the distinct ones).

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

The square root of 13720640 is about 3704.1382263625. The cubic root of 13720640 is about 239.4003548735.

The spelling of 13720640 in words is "thirteen million, seven hundred twenty thousand, six hundred forty".