156668689 has 4 divisors (see below), whose sum is σ = 159624756. Its totient is φ = 153712624.

The previous prime is 156668669. The next prime is 156668723. The reversal of 156668689 is 986866651.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 141419664 + 15249025 = 11892^2 + 3905^2 .

It is a cyclic number.

It is not a de Polignac number, because 156668689 - 2⁵ = 156668657 is a prime.

It is a super-2 number, since 2×156668689² = 49090156225957442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156668609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1477954 + ... + 1478059.

It is an arithmetic number, because the mean of its divisors is an integer number (39906189).

Almost surely, 2^156668689 is an apocalyptic number.

It is an amenable number.

156668689 is a deficient number, since it is larger than the sum of its proper divisors (2956067).

156668689 is an equidigital number, since it uses as much as digits as its factorization.

156668689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2956066.

The product of its digits is 3732480, while the sum is 55.

The square root of 156668689 is about 12516.7363557758. The cubic root of 156668689 is about 539.0893304279.

The spelling of 156668689 in words is "one hundred fifty-six million, six hundred sixty-eight thousand, six hundred eighty-nine".