170721013 has 2 divisors, whose sum is σ = 170721014. Its totient is φ = 170721012.

The previous prime is 170721011. The next prime is 170721041. The reversal of 170721013 is 310127071.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 101465329 + 69255684 = 10073^2 + 8322^2 .

It is a cyclic number.

It is not a de Polignac number, because 170721013 - 2¹ = 170721011 is a prime.

Together with 170721011, it forms a pair of twin primes.

It is equal to p_9541120 and since 170721013 and 9541120 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (170721011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85360506 + 85360507.

It is an arithmetic number, because the mean of its divisors is an integer number (85360507).

Almost surely, 2^170721013 is an apocalyptic number.

It is an amenable number.

170721013 is a deficient number, since it is larger than the sum of its proper divisors (1).

170721013 is an equidigital number, since it uses as much as digits as its factorization.

170721013 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 170721013 is about 13066.0251415647. The cubic root of 170721013 is about 554.7478907991.

Adding to 170721013 its reverse (310127071), we get a palindrome (480848084).

The spelling of 170721013 in words is "one hundred seventy million, seven hundred twenty-one thousand, thirteen".