13503721 has 24 divisors (see below), whose sum is σ = 17236800. Its totient is φ = 10354080.

The previous prime is 13503713. The next prime is 13503733. The reversal of 13503721 is 12730531.

13503721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 13503721 - 2³ = 13503713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13503692 and 13503701.

It is not an unprimeable number, because it can be changed into a prime (13503751) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 90555 + ... + 90703.

It is an arithmetic number, because the mean of its divisors is an integer number (718200).

Almost surely, 2^13503721 is an apocalyptic number.

13503721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13503721 is a deficient number, since it is larger than the sum of its proper divisors (3733079).

13503721 is a wasteful number, since it uses less digits than its factorization.

13503721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 13503721 is about 3674.7409432503. The cubic root of 13503721 is about 238.1320325238.

The spelling of 13503721 in words is "thirteen million, five hundred three thousand, seven hundred twenty-one".