661930 has 16 divisors (see below), whose sum is σ = 1224360. Its totient is φ = 257472.

The previous prime is 661909. The next prime is 661931. The reversal of 661930 is 39166.

It can be written as a sum of positive squares in 4 ways, for example, as 660969 + 961 = 813^2 + 31^2 .

It is a junction number, because it is equal to n+sod(n) for n = 661895 and 661904.

It is not an unprimeable number, because it can be changed into a prime (661931) 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, 525 + ... + 1264.

2⁶⁶¹⁹³⁰ is an apocalyptic number.

661930 is a deficient number, since it is larger than the sum of its proper divisors (562430).

661930 is a wasteful number, since it uses less digits than its factorization.

661930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1833.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 661930 is about 813.5908062411. The cubic root of 661930 is about 87.1506615654.

The spelling of 661930 in words is "six hundred sixty-one thousand, nine hundred thirty".