20939440 has 40 divisors (see below), whose sum is σ = 49728960. Its totient is φ = 8196096.

The previous prime is 20939419. The next prime is 20939459. The reversal of 20939440 is 4493902.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 976 + ... + 6544.

It is an arithmetic number, because the mean of its divisors is an integer number (1243224).

Almost surely, 2^20939440 is an apocalyptic number.

20939440 is a gapful number since it is divisible by the number (20) 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 20939440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24864480).

20939440 is an abundant number, since it is smaller than the sum of its proper divisors (28789520).

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

20939440 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (20939439) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (5629).

20939440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5629 (or 5623 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20939440 is about 4575.9632865660. The cubic root of 20939440 is about 275.6269552328.

The spelling of 20939440 in words is "twenty million, nine hundred thirty-nine thousand, four hundred forty".