661156 has 12 divisors (see below), whose sum is σ = 1174768. Its totient is φ = 325512.

The previous prime is 661139. The next prime is 661183. The reversal of 661156 is 651166.

It is a self number, because there is not a number n which added to its sum of digits gives 661156.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 966 + ... + 1501.

2⁶⁶¹¹⁵⁶ is an apocalyptic number.

It is an amenable number.

661156 is a deficient number, since it is larger than the sum of its proper divisors (513612).

661156 is a wasteful number, since it uses less digits than its factorization.

661156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2538 (or 2536 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 661156 is about 813.1149980169. The cubic root of 661156 is about 87.1166796635.

The spelling of 661156 in words is "six hundred sixty-one thousand, one hundred fifty-six".