20924640 has 144 divisors (see below), whose sum is σ = 77955696. Its totient is φ = 5068800.

The previous prime is 20924639. The next prime is 20924693. The reversal of 20924640 is 4642902.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15180 + ... + 16500.

It is an arithmetic number, because the mean of its divisors is an integer number (541359).

Almost surely, 2^20924640 is an apocalyptic number.

20924640 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 20924640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38977848).

20924640 is an abundant number, since it is smaller than the sum of its proper divisors (57031056).

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

20924640 is a wasteful number, since it uses less digits than its factorization.

20924640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1353 (or 1342 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 20924640 is about 4574.3458548737. The cubic root of 20924640 is about 275.5620022001.

The spelling of 20924640 in words is "twenty million, nine hundred twenty-four thousand, six hundred forty".