21946824 has 96 divisors (see below), whose sum is σ = 63835200. Its totient is φ = 6791040.

The previous prime is 21946819. The next prime is 21946829. The reversal of 21946824 is 42864912.

It is an interprime number because it is at equal distance from previous prime (21946819) and next prime (21946829).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21946829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83317 + ... + 83579.

It is an arithmetic number, because the mean of its divisors is an integer number (664950).

Almost surely, 2^21946824 is an apocalyptic number.

21946824 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 21946824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31917600).

21946824 is an abundant number, since it is smaller than the sum of its proper divisors (41888376).

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

21946824 is a wasteful number, since it uses less digits than its factorization.

21946824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 348 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21946824 is about 4684.7437496623. The cubic root of 21946824 is about 279.9779914674.

The spelling of 21946824 in words is "twenty-one million, nine hundred forty-six thousand, eight hundred twenty-four".