18681856 has 26 divisors (see below), whose sum is σ = 37367342. Its totient is φ = 9338880.

The previous prime is 18681853. The next prime is 18681857. The reversal of 18681856 is 65818681.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 14745600 + 3936256 = 3840^2 + 1984^2 .

It is not an unprimeable number, because it can be changed into a prime (18681851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1816 + ... + 6376.

Almost surely, 2^18681856 is an apocalyptic number.

18681856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18681856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18683671).

18681856 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

18681856 is an frugal number, since it uses more digits than its factorization.

18681856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4585 (or 4563 counting only the distinct ones).

The product of its digits is 92160, while the sum is 43.

The square root of 18681856 is about 4322.2512652552. The cubic root of 18681856 is about 265.3424124791.

The spelling of 18681856 in words is "eighteen million, six hundred eighty-one thousand, eight hundred fifty-six".