661923 has 6 divisors (see below), whose sum is σ = 956124. Its totient is φ = 441276.

The previous prime is 661909. The next prime is 661931. The reversal of 661923 is 329166.

It is a happy number.

It is not a de Polignac number, because 661923 - 2¹⁰ = 660899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661993) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36765 + ... + 36782.

It is an arithmetic number, because the mean of its divisors is an integer number (159354).

2⁶⁶¹⁹²³ is an apocalyptic number.

661923 is a deficient number, since it is larger than the sum of its proper divisors (294201).

661923 is a wasteful number, since it uses less digits than its factorization.

661923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73553 (or 73550 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 661923 is about 813.5865043128. The cubic root of 661923 is about 87.1503543543.

The spelling of 661923 in words is "six hundred sixty-one thousand, nine hundred twenty-three".