13985721 has 12 divisors (see below), whose sum is σ = 20235072. Its totient is φ = 9308376.

The previous prime is 13985711. The next prime is 13985731. The reversal of 13985721 is 12758931.

It is an interprime number because it is at equal distance from previous prime (13985711) and next prime (13985731).

It is not a de Polignac number, because 13985721 - 2¹⁴ = 13969337 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13985711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7900 + ... + 9506.

It is an arithmetic number, because the mean of its divisors is an integer number (1686256).

Almost surely, 2^13985721 is an apocalyptic number.

It is an amenable number.

13985721 is a deficient number, since it is larger than the sum of its proper divisors (6249351).

13985721 is a wasteful number, since it uses less digits than its factorization.

13985721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2580 (or 2577 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 13985721 is about 3739.7487883546. The cubic root of 13985721 is about 240.9322594458.

It can be divided in two parts, 13985 and 721, that added together give a triangular number (14706 = T₁₇₁).

The spelling of 13985721 in words is "thirteen million, nine hundred eighty-five thousand, seven hundred twenty-one".