661908 has 24 divisors (see below), whose sum is σ = 1663648. Its totient is φ = 203616.

The previous prime is 661897. The next prime is 661909. The reversal of 661908 is 809166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661909) by changing a digit.

661908 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 7 ways as a sum of consecutive naturals, for example, 1966 + ... + 2277.

2⁶⁶¹⁹⁰⁸ is an apocalyptic number.

It is an amenable number.

661908 is an abundant number, since it is smaller than the sum of its proper divisors (1001740).

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

661908 is a wasteful number, since it uses less digits than its factorization.

661908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4263 (or 4261 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 661908 is about 813.5772858186. The cubic root of 661908 is about 87.1496960374.

The spelling of 661908 in words is "six hundred sixty-one thousand, nine hundred eight".