20821944 has 64 divisors (see below), whose sum is σ = 61165440. Its totient is φ = 5823360.

The previous prime is 20821909. The next prime is 20821949. The reversal of 20821944 is 44912802.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20821949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 399 + ... + 6465.

It is an arithmetic number, because the mean of its divisors is an integer number (955710).

Almost surely, 2^20821944 is an apocalyptic number.

20821944 is a gapful number since it is divisible by the number (24) 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 20821944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30582720).

20821944 is an abundant number, since it is smaller than the sum of its proper divisors (40343496).

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

20821944 is a wasteful number, since it uses less digits than its factorization.

20821944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6100 (or 6096 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 20821944 is about 4563.1068363561. The cubic root of 20821944 is about 275.1104526009.

The spelling of 20821944 in words is "twenty million, eight hundred twenty-one thousand, nine hundred forty-four".