20531984 has 40 divisors (see below), whose sum is σ = 44422752. Its totient is φ = 9112320.

The previous prime is 20531983. The next prime is 20531999. The reversal of 20531984 is 48913502.

It is a self number, because there is not a number n which added to its sum of digits gives 20531984.

It is not an unprimeable number, because it can be changed into a prime (20531981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6212 + ... + 8924.

Almost surely, 2^20531984 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 20531984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22211376).

20531984 is an abundant number, since it is smaller than the sum of its proper divisors (23890768).

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

20531984 is a wasteful number, since it uses less digits than its factorization.

20531984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2775 (or 2769 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 20531984 is about 4531.2232344037. The cubic root of 20531984 is about 273.8274438772.

The spelling of 20531984 in words is "twenty million, five hundred thirty-one thousand, nine hundred eighty-four".