661339 has 4 divisors (see below), whose sum is σ = 755824. Its totient is φ = 566856.

The previous prime is 661327. The next prime is 661343. The reversal of 661339 is 933166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661339 - 2¹⁷ = 530267 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47232 + ... + 47245.

It is an arithmetic number, because the mean of its divisors is an integer number (188956).

2⁶⁶¹³³⁹ is an apocalyptic number.

661339 is a deficient number, since it is larger than the sum of its proper divisors (94485).

661339 is an equidigital number, since it uses as much as digits as its factorization.

661339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94484.

The product of its digits is 2916, while the sum is 28.

The square root of 661339 is about 813.2275204394. The cubic root of 661339 is about 87.1247165372.

It can be divided in two parts, 661 and 339, that added together give a cube (1000 = 10³).

The spelling of 661339 in words is "six hundred sixty-one thousand, three hundred thirty-nine".