20428704 has 72 divisors (see below), whose sum is σ = 58820580. Its totient is φ = 6724608.

The previous prime is 20428697. The next prime is 20428739. The reversal of 20428704 is 40782402.

It can be written as a sum of positive squares in 2 ways, for example, as 19820304 + 608400 = 4452^2 + 780^2 .

It is a tau number, because it is divible by the number of its divisors (72).

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, 25234 + ... + 26030.

Almost surely, 2^20428704 is an apocalyptic number.

20428704 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 20428704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29410290).

20428704 is an abundant number, since it is smaller than the sum of its proper divisors (38391876).

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

20428704 is a wasteful number, since it uses less digits than its factorization.

20428704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902 (or 891 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 20428704 is about 4519.8123854868. The cubic root of 20428704 is about 273.3675362051.

The spelling of 20428704 in words is "twenty million, four hundred twenty-eight thousand, seven hundred four".