18685840 has 40 divisors (see below), whose sum is σ = 43800768. Its totient is φ = 7413120.

The previous prime is 18685801. The next prime is 18685853. The reversal of 18685840 is 4858681.

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

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 18685793 and 18685802.

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, 9589 + ... + 11371.

Almost surely, 2^18685840 is an apocalyptic number.

18685840 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 18685840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21900384).

18685840 is an abundant number, since it is smaller than the sum of its proper divisors (25114928).

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

18685840 is a wasteful number, since it uses less digits than its factorization.

18685840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1927 (or 1921 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 40.

The square root of 18685840 is about 4322.7121116262. The cubic root of 18685840 is about 265.3612730077.

The spelling of 18685840 in words is "eighteen million, six hundred eighty-five thousand, eight hundred forty".