20304720 has 60 divisors (see below), whose sum is σ = 68192436. Its totient is φ = 5414400.

The previous prime is 20304701. The next prime is 20304733. The reversal of 20304720 is 2740302.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10419984 + 9884736 = 3228^2 + 3144^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20304693 and 20304702.

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, 13381 + ... + 14820.

Almost surely, 2^20304720 is an apocalyptic number.

20304720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20304720 is an abundant number, since it is smaller than the sum of its proper divisors (47887716).

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

20304720 is a wasteful number, since it uses less digits than its factorization.

20304720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28220 (or 28211 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 18.

The square root of 20304720 is about 4506.0758981624. The cubic root of 20304720 is about 272.8133812948.

The spelling of 20304720 in words is "twenty million, three hundred four thousand, seven hundred twenty".