18181968 has 80 divisors (see below), whose sum is σ = 54746496. Its totient is φ = 5091840.

The previous prime is 18181967. The next prime is 18181981. The reversal of 18181968 is 86918181.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18181967) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17298 + ... + 18318.

Almost surely, 2^18181968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18181968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27373248).

18181968 is an abundant number, since it is smaller than the sum of its proper divisors (36564528).

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

18181968 is a wasteful number, since it uses less digits than its factorization.

18181968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1092 (or 1086 counting only the distinct ones).

The product of its digits is 27648, while the sum is 42.

The square root of 18181968 is about 4264.0318948150. The cubic root of 18181968 is about 262.9543116768.

The spelling of 18181968 in words is "eighteen million, one hundred eighty-one thousand, nine hundred sixty-eight".