660990 has 32 divisors (see below), whose sum is σ = 1731456. Its totient is φ = 160160.

The previous prime is 660983. The next prime is 661009. The reversal of 660990 is 99066.

It is a Harshad number since it is a multiple of its sum of digits (30).

660990 is a modest number, since divided by 990 gives 660 as remainder.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

660990 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 672 + ... + 1331.

It is an arithmetic number, because the mean of its divisors is an integer number (54108).

2⁶⁶⁰⁹⁹⁰ is an apocalyptic number.

660990 is an abundant number, since it is smaller than the sum of its proper divisors (1070466).

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

660990 is a wasteful number, since it uses less digits than its factorization.

660990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2024.

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 660990 is about 813.0129150266. The cubic root of 660990 is about 87.1093881018.

It can be divided in two parts, 6 and 60990, that multiplied together give a triangular number (365940 = T₈₅₅).

The spelling of 660990 in words is "six hundred sixty thousand, nine hundred ninety".