13170721 has 2 divisors, whose sum is σ = 13170722. Its totient is φ = 13170720.

The previous prime is 13170679. The next prime is 13170739. The reversal of 13170721 is 12707131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12680721 + 490000 = 3561^2 + 700^2 .

It is a cyclic number.

It is not a de Polignac number, because 13170721 - 2⁷ = 13170593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13170692 and 13170701.

It is not a weakly prime, because it can be changed into another prime (13170761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6585360 + 6585361.

It is an arithmetic number, because the mean of its divisors is an integer number (6585361).

Almost surely, 2^13170721 is an apocalyptic number.

It is an amenable number.

13170721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13170721 is an equidigital number, since it uses as much as digits as its factorization.

13170721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 13170721 is about 3629.1487982721. The cubic root of 13170721 is about 236.1582834079.

Adding to 13170721 its reverse (12707131), we get a palindrome (25877852).

The spelling of 13170721 in words is "thirteen million, one hundred seventy thousand, seven hundred twenty-one".