13721421 has 24 divisors (see below), whose sum is σ = 21422880. Its totient is φ = 7789152.

The previous prime is 13721419. The next prime is 13721423. The reversal of 13721421 is 12412731.

13721421 is digitally balanced in base 3, because in such base 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 (13721419) and next prime (13721423).

It is not a de Polignac number, because 13721421 - 2¹ = 13721419 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13721423) 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, 39370 + ... + 39716.

It is an arithmetic number, because the mean of its divisors is an integer number (892620).

Almost surely, 2^13721421 is an apocalyptic number.

It is an amenable number.

13721421 is a deficient number, since it is larger than the sum of its proper divisors (7701459).

13721421 is a wasteful number, since it uses less digits than its factorization.

13721421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 633 (or 626 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 13721421 is about 3704.2436474940. The cubic root of 13721421 is about 239.4048971332.

The spelling of 13721421 in words is "thirteen million, seven hundred twenty-one thousand, four hundred twenty-one".