661636 has 12 divisors (see below), whose sum is σ = 1164240. Its totient is φ = 329000.

The previous prime is 661621. The next prime is 661663. The reversal of 661636 is 636166.

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, 675 + ... + 1333.

It is an arithmetic number, because the mean of its divisors is an integer number (97020).

2⁶⁶¹⁶³⁶ is an apocalyptic number.

It is an amenable number.

661636 is a deficient number, since it is larger than the sum of its proper divisors (502604).

661636 is a wasteful number, since it uses less digits than its factorization.

661636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 914 (or 912 counting only the distinct ones).

The product of its digits is 3888, while the sum is 28.

The square root of 661636 is about 813.4101056663. The cubic root of 661636 is about 87.1377568328.

The spelling of 661636 in words is "six hundred sixty-one thousand, six hundred thirty-six".