20399184 has 120 divisors (see below), whose sum is σ = 65198952. Its totient is φ = 5898240.

The previous prime is 20399177. The next prime is 20399213. The reversal of 20399184 is 48199302.

It can be written as a sum of positive squares in 4 ways, for example, as 6110784 + 14288400 = 2472^2 + 3780^2 .

It is a super-2 number, since 2×20399184² = 832253415731712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31504 + ... + 32144.

Almost surely, 2^20399184 is an apocalyptic number.

20399184 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 20399184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32599476).

20399184 is an abundant number, since it is smaller than the sum of its proper divisors (44799768).

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

20399184 is a wasteful number, since it uses less digits than its factorization.

20399184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685 (or 676 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 20399184 is about 4516.5455826328. The cubic root of 20399184 is about 273.2357983683.

The spelling of 20399184 in words is "twenty million, three hundred ninety-nine thousand, one hundred eighty-four".