20499984 has 60 divisors (see below), whose sum is σ = 59361900. Its totient is φ = 6596352.

The previous prime is 20499971. The next prime is 20500019. The reversal of 20499984 is 48999402.

It can be written as a sum of positive squares in 2 ways, for example, as 17040384 + 3459600 = 4128^2 + 1860^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1722 + ... + 6630.

It is an arithmetic number, because the mean of its divisors is an integer number (989365).

Almost surely, 2^20499984 is an apocalyptic number.

20499984 is a gapful number since it is divisible by the number (24) 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 20499984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29680950).

20499984 is an abundant number, since it is smaller than the sum of its proper divisors (38861916).

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

20499984 is a wasteful number, since it uses less digits than its factorization.

20499984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4952 (or 4943 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 20499984 is about 4527.6908021639. The cubic root of 20499984 is about 273.6851125373.

The spelling of 20499984 in words is "twenty million, four hundred ninety-nine thousand, nine hundred eighty-four".