661964 has 12 divisors (see below), whose sum is σ = 1174824. Its totient is φ = 326304.

The previous prime is 661961. The next prime is 661987. The reversal of 661964 is 469166.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 661964.

It is not an unprimeable number, because it can be changed into a prime (661961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842 + ... + 1425.

It is an arithmetic number, because the mean of its divisors is an integer number (97902).

2⁶⁶¹⁹⁶⁴ is an apocalyptic number.

It is an amenable number.

661964 is a deficient number, since it is larger than the sum of its proper divisors (512860).

661964 is a wasteful number, since it uses less digits than its factorization.

661964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2344 (or 2342 counting only the distinct ones).

The product of its digits is 7776, while the sum is 32.

The square root of 661964 is about 813.6117009975. The cubic root of 661964 is about 87.1521537029.

The spelling of 661964 in words is "six hundred sixty-one thousand, nine hundred sixty-four".