156561 has 8 divisors (see below), whose sum is σ = 217920. Its totient is φ = 99792.

The previous prime is 156539. The next prime is 156577. The reversal of 156561 is 165651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 156561 - 2¹⁰ = 155537 is a prime.

It is a super-2 number, since 2×156561² = 49022693442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (156511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1066 + ... + 1203.

It is an arithmetic number, because the mean of its divisors is an integer number (27240).

2¹⁵⁶⁵⁶¹ is an apocalyptic number.

It is an amenable number.

156561 is a deficient number, since it is larger than the sum of its proper divisors (61359).

156561 is a wasteful number, since it uses less digits than its factorization.

156561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2295.

The product of its digits is 900, while the sum is 24.

The square root of 156561 is about 395.6778993070. The cubic root of 156561 is about 53.8965784581.

It can be divided in two parts, 156 and 561, that added together give a palindrome (717).

The spelling of 156561 in words is "one hundred fifty-six thousand, five hundred sixty-one".