20309072 has 40 divisors (see below), whose sum is σ = 46026816. Its totient is φ = 8499456.

The previous prime is 20309071. The next prime is 20309087. The reversal of 20309072 is 27090302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20309071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2708 + ... + 6924.

Almost surely, 2^20309072 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 20309072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23013408).

20309072 is an abundant number, since it is smaller than the sum of its proper divisors (25717744).

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

20309072 is a wasteful number, since it uses less digits than its factorization.

20309072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4275 (or 4269 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 20309072 is about 4506.5587758288. The cubic root of 20309072 is about 272.8328710000.

Adding to 20309072 its reverse (27090302), we get a palindrome (47399374).

The spelling of 20309072 in words is "twenty million, three hundred nine thousand, seventy-two".