20187840 has 112 divisors (see below), whose sum is σ = 67921632. Its totient is φ = 5062656.

The previous prime is 20187833. The next prime is 20187887. The reversal of 20187840 is 4878102.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20187798 and 20187807.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15702 + ... + 16938.

Almost surely, 2^20187840 is an apocalyptic number.

20187840 is a gapful number since it is divisible by the number (20) 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 20187840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33960816).

20187840 is an abundant number, since it is smaller than the sum of its proper divisors (47733792).

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

20187840 is a wasteful number, since it uses less digits than its factorization.

20187840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1274 (or 1264 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 20187840 is about 4493.0880249557. The cubic root of 20187840 is about 272.2889087091.

The spelling of 20187840 in words is "twenty million, one hundred eighty-seven thousand, eight hundred forty".