170706721 has 2 divisors, whose sum is σ = 170706722. Its totient is φ = 170706720.

The previous prime is 170706709. The next prime is 170706737. The reversal of 170706721 is 127607071.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133056225 + 37650496 = 11535^2 + 6136^2 .

It is a cyclic number.

It is not a de Polignac number, because 170706721 - 2¹⁷ = 170575649 is a prime.

It is equal to p_9540373 and since 170706721 and 9540373 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (170706761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85353360 + 85353361.

It is an arithmetic number, because the mean of its divisors is an integer number (85353361).

Almost surely, 2^170706721 is an apocalyptic number.

It is an amenable number.

170706721 is a deficient number, since it is larger than the sum of its proper divisors (1).

170706721 is an equidigital number, since it uses as much as digits as its factorization.

170706721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4116, while the sum is 31.

The square root of 170706721 is about 13065.4782155113. The cubic root of 170706721 is about 554.7324100293.

The spelling of 170706721 in words is "one hundred seventy million, seven hundred six thousand, seven hundred twenty-one".