156409661 has 2 divisors, whose sum is σ = 156409662. Its totient is φ = 156409660.

The previous prime is 156409657. The next prime is 156409667. The reversal of 156409661 is 166904651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93508900 + 62900761 = 9670^2 + 7931^2 .

It is a cyclic number.

It is not a de Polignac number, because 156409661 - 2² = 156409657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156409667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78204830 + 78204831.

It is an arithmetic number, because the mean of its divisors is an integer number (78204831).

Almost surely, 2^156409661 is an apocalyptic number.

It is an amenable number.

156409661 is a deficient number, since it is larger than the sum of its proper divisors (1).

156409661 is an equidigital number, since it uses as much as digits as its factorization.

156409661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 156409661 is about 12506.3848093684. The cubic root of 156409661 is about 538.7920656284.

The spelling of 156409661 in words is "one hundred fifty-six million, four hundred nine thousand, six hundred sixty-one".