661836 has 24 divisors (see below), whose sum is σ = 1765120. Its totient is φ = 189072.

The previous prime is 661823. The next prime is 661849. The reversal of 661836 is 638166.

It is an interprime number because it is at equal distance from previous prime (661823) and next prime (661849).

It is an unprimeable number.

661836 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, 3856 + ... + 4023.

2⁶⁶¹⁸³⁶ is an apocalyptic number.

It is an amenable number.

661836 is an abundant number, since it is smaller than the sum of its proper divisors (1103284).

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

661836 is a wasteful number, since it uses less digits than its factorization.

661836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7893 (or 7891 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 661836 is about 813.5330355923. The cubic root of 661836 is about 87.1465359781.

The spelling of 661836 in words is "six hundred sixty-one thousand, eight hundred thirty-six".