661239 has 6 divisors (see below), whose sum is σ = 955136. Its totient is φ = 440820.

The previous prime is 661237. The next prime is 661253. The reversal of 661239 is 932166.

It is a happy number.

It is not a de Polignac number, because 661239 - 2¹ = 661237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661231) 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, 36727 + ... + 36744.

2⁶⁶¹²³⁹ is an apocalyptic number.

661239 is a deficient number, since it is larger than the sum of its proper divisors (293897).

661239 is a wasteful number, since it uses less digits than its factorization.

661239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73477 (or 73474 counting only the distinct ones).

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

The square root of 661239 is about 813.1660347063. The cubic root of 661239 is about 87.1203249867.

It can be divided in two parts, 661 and 239, that added together give a square (900 = 30²).

The spelling of 661239 in words is "six hundred sixty-one thousand, two hundred thirty-nine".