661590 has 24 divisors (see below), whose sum is σ = 1720368. Its totient is φ = 176400.

The previous prime is 661553. The next prime is 661603. The reversal of 661590 is 95166.

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661590.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3586 + ... + 3765.

It is an arithmetic number, because the mean of its divisors is an integer number (71682).

2⁶⁶¹⁵⁹⁰ is an apocalyptic number.

661590 is an abundant number, since it is smaller than the sum of its proper divisors (1058778).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661590 is a wasteful number, since it uses less digits than its factorization.

661590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7364 (or 7361 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 661590 is about 813.3818291553. The cubic root of 661590 is about 87.1357373792.

The spelling of 661590 in words is "six hundred sixty-one thousand, five hundred ninety".