156005661 has 16 divisors (see below), whose sum is σ = 242576000. Its totient is φ = 89145504.

The previous prime is 156005623. The next prime is 156005669. The reversal of 156005661 is 166500651.

156005661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 156005661 - 2¹⁰ = 156004637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156005669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74776 + ... + 76833.

It is an arithmetic number, because the mean of its divisors is an integer number (15161000).

Almost surely, 2^156005661 is an apocalyptic number.

It is an amenable number.

156005661 is a deficient number, since it is larger than the sum of its proper divisors (86570339).

156005661 is an equidigital number, since it uses as much as digits as its factorization.

156005661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151633 (or 151619 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 156005661 is about 12490.2226161106. Note that the first 3 decimals coincide. The cubic root of 156005661 is about 538.3277727468.

The spelling of 156005661 in words is "one hundred fifty-six million, five thousand, six hundred sixty-one".