18871840 has 96 divisors (see below), whose sum is σ = 49363776. Its totient is φ = 6773760.

The previous prime is 18871789. The next prime is 18871841. The reversal of 18871840 is 4817881.

It is a super-2 number, since 2×18871840² = 712292689971200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18871840.

It is not an unprimeable number, because it can be changed into a prime (18871841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89335 + ... + 89545.

It is an arithmetic number, because the mean of its divisors is an integer number (514206).

Almost surely, 2^18871840 is an apocalyptic number.

18871840 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 18871840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24681888).

18871840 is an abundant number, since it is smaller than the sum of its proper divisors (30491936).

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

18871840 is a wasteful number, since it uses less digits than its factorization.

18871840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 18871840 is about 4344.1731088897. The cubic root of 18871840 is about 266.2388417668.

The spelling of 18871840 in words is "eighteen million, eight hundred seventy-one thousand, eight hundred forty".