18681966 has 24 divisors (see below), whose sum is σ = 41573064. Its totient is φ = 6058800.

The previous prime is 18681961. The next prime is 18681967. The reversal of 18681966 is 66918681.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18681961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13360 + ... + 14691.

It is an arithmetic number, because the mean of its divisors is an integer number (1732211).

Almost surely, 2^18681966 is an apocalyptic number.

18681966 is an abundant number, since it is smaller than the sum of its proper divisors (22891098).

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

18681966 is a wasteful number, since it uses less digits than its factorization.

18681966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28096 (or 28093 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 18681966 is about 4322.2639900867. The cubic root of 18681966 is about 265.3429332626.

The spelling of 18681966 in words is "eighteen million, six hundred eighty-one thousand, nine hundred sixty-six".