661900 has 18 divisors (see below), whose sum is σ = 1436540. Its totient is φ = 264720.

The previous prime is 661897. The next prime is 661909. The reversal of 661900 is 9166.

It is a super-2 number, since 2×661900² = 876223220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661909) 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, 3210 + ... + 3409.

2⁶⁶¹⁹⁰⁰ is an apocalyptic number.

It is an amenable number.

661900 is an abundant number, since it is smaller than the sum of its proper divisors (774640).

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

661900 is a wasteful number, since it uses less digits than its factorization.

661900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6633 (or 6626 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 661900 is about 813.5723692457. The cubic root of 661900 is about 87.1493449310.

The spelling of 661900 in words is "six hundred sixty-one thousand, nine hundred".