13078721 has 2 divisors, whose sum is σ = 13078722. Its totient is φ = 13078720.

The previous prime is 13078699. The next prime is 13078771. The reversal of 13078721 is 12787031.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8065600 + 5013121 = 2840^2 + 2239^2 .

It is a cyclic number.

It is not a de Polignac number, because 13078721 - 2⁶ = 13078657 is a prime.

It is not a weakly prime, because it can be changed into another prime (13078771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6539360 + 6539361.

It is an arithmetic number, because the mean of its divisors is an integer number (6539361).

Almost surely, 2^13078721 is an apocalyptic number.

It is an amenable number.

13078721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13078721 is an equidigital number, since it uses as much as digits as its factorization.

13078721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 13078721 is about 3616.4514375282. The cubic root of 13078721 is about 235.6071278721.

The spelling of 13078721 in words is "thirteen million, seventy-eight thousand, seven hundred twenty-one".