21394944 has 60 divisors (see below), whose sum is σ = 61760556. Its totient is φ = 7130112.

The previous prime is 21394943. The next prime is 21394949. The reversal of 21394944 is 44949312.

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 a junction number, because it is equal to n+sod(n) for n = 21394899 and 21394908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394943) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2287 + ... + 6929.

Almost surely, 2^21394944 is an apocalyptic number.

21394944 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 21394944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30880278).

21394944 is an abundant number, since it is smaller than the sum of its proper divisors (40365612).

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

21394944 is an equidigital number, since it uses as much as digits as its factorization.

21394944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4667 (or 4648 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21394944 is about 4625.4668953523. The cubic root of 21394944 is about 277.6112434439.

The spelling of 21394944 in words is "twenty-one million, three hundred ninety-four thousand, nine hundred forty-four".