661925 has 24 divisors (see below), whose sum is σ = 937440. Its totient is φ = 459200.

The previous prime is 661909. The next prime is 661931. The reversal of 661925 is 529166.

It is not a de Polignac number, because 661925 - 2⁴ = 661909 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7934 + ... + 8016.

It is an arithmetic number, because the mean of its divisors is an integer number (39060).

2⁶⁶¹⁹²⁵ is an apocalyptic number.

It is an amenable number.

661925 is a deficient number, since it is larger than the sum of its proper divisors (275515).

661925 is a wasteful number, since it uses less digits than its factorization.

661925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 128 counting only the distinct ones).

The product of its digits is 3240, while the sum is 29.

The square root of 661925 is about 813.5877334375. The cubic root of 661925 is about 87.1504421291.

It can be divided in two parts, 66 and 1925, that added together give a palindrome (1991).

The spelling of 661925 in words is "six hundred sixty-one thousand, nine hundred twenty-five".