13458721 has 2 divisors, whose sum is σ = 13458722. Its totient is φ = 13458720.

The previous prime is 13458691. The next prime is 13458727. The reversal of 13458721 is 12785431.

13458721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13140625 + 318096 = 3625^2 + 564^2 .

It is a cyclic number.

It is not a de Polignac number, because 13458721 - 2¹⁵ = 13425953 is a prime.

It is a super-2 number, since 2×13458721² = 362274341911682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13458727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6729360 + 6729361.

It is an arithmetic number, because the mean of its divisors is an integer number (6729361).

Almost surely, 2^13458721 is an apocalyptic number.

It is an amenable number.

13458721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13458721 is an equidigital number, since it uses as much as digits as its factorization.

13458721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 31.

The square root of 13458721 is about 3668.6129531473. The cubic root of 13458721 is about 237.8672199122.

The spelling of 13458721 in words is "thirteen million, four hundred fifty-eight thousand, seven hundred twenty-one".