18881840 has 40 divisors (see below), whose sum is σ = 45093840. Its totient is φ = 7347456.

The previous prime is 18881809. The next prime is 18881861. The reversal of 18881840 is 4818881.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 18881794 and 18881803.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 230 + ... + 6149.

It is an arithmetic number, because the mean of its divisors is an integer number (1127346).

Almost surely, 2^18881840 is an apocalyptic number.

18881840 is a gapful number since it is divisible by the number (10) 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 18881840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22546920).

18881840 is an abundant number, since it is smaller than the sum of its proper divisors (26212000).

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

18881840 is a wasteful number, since it uses less digits than its factorization.

18881840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6429 (or 6423 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 38.

The square root of 18881840 is about 4345.3239234837. The cubic root of 18881840 is about 266.2858592330.

It can be divided in two parts, 188 and 81840, that added together give a palindrome (82028).

The spelling of 18881840 in words is "eighteen million, eight hundred eighty-one thousand, eight hundred forty".