21994944 has 56 divisors (see below), whose sum is σ = 58844688. Its totient is φ = 7249920.

The previous prime is 21994897. The next prime is 21994981. The reversal of 21994944 is 44949912.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21994896 and 21994905.

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 7 ways as a sum of consecutive naturals, for example, 18034 + ... + 19214.

It is an arithmetic number, because the mean of its divisors is an integer number (1050798).

Almost surely, 2^21994944 is an apocalyptic number.

21994944 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 21994944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29422344).

21994944 is an abundant number, since it is smaller than the sum of its proper divisors (36849744).

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

21994944 is a wasteful number, since it uses less digits than its factorization.

21994944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1293 (or 1283 counting only the distinct ones).

The product of its digits is 93312, while the sum is 42.

The square root of 21994944 is about 4689.8767574426. The cubic root of 21994944 is about 280.1824661015.

The spelling of 21994944 in words is "twenty-one million, nine hundred ninety-four thousand, nine hundred forty-four".