18661956 has 12 divisors (see below), whose sum is σ = 43544592. Its totient is φ = 6220648.

The previous prime is 18661943. The next prime is 18661963. The reversal of 18661956 is 65916681.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 777570 + ... + 777593.

It is an arithmetic number, because the mean of its divisors is an integer number (3628716).

Almost surely, 2^18661956 is an apocalyptic number.

It is an amenable number.

18661956 is an abundant number, since it is smaller than the sum of its proper divisors (24882636).

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

18661956 is a wasteful number, since it uses less digits than its factorization.

18661956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555170 (or 1555168 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The square root of 18661956 is about 4319.9486108055. The cubic root of 18661956 is about 265.2481643489.

The spelling of 18661956 in words is "eighteen million, six hundred sixty-one thousand, nine hundred fifty-six".