20309472 has 72 divisors (see below), whose sum is σ = 58430736. Its totient is φ = 6690816.

The previous prime is 20309453. The next prime is 20309489. The reversal of 20309472 is 27490302.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27573 + ... + 28299.

It is an arithmetic number, because the mean of its divisors is an integer number (811538).

Almost surely, 2^20309472 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 20309472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29215368).

20309472 is an abundant number, since it is smaller than the sum of its proper divisors (38121264).

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

20309472 is a wasteful number, since it uses less digits than its factorization.

20309472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840 (or 829 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 20309472 is about 4506.6031553710. The cubic root of 20309472 is about 272.8346621935.

Adding to 20309472 its reverse (27490302), we get a palindrome (47799774).

The spelling of 20309472 in words is "twenty million, three hundred nine thousand, four hundred seventy-two".