21749364 has 96 divisors (see below), whose sum is σ = 69431040. Its totient is φ = 5733504.

The previous prime is 21749353. The next prime is 21749419. The reversal of 21749364 is 46394712.

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 congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8722 + ... + 10934.

It is an arithmetic number, because the mean of its divisors is an integer number (723240).

Almost surely, 2^21749364 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21749364, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34715520).

21749364 is an abundant number, since it is smaller than the sum of its proper divisors (47681676).

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

21749364 is a wasteful number, since it uses less digits than its factorization.

21749364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2246 (or 2238 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 21749364 is about 4663.6213396887. The cubic root of 21749364 is about 279.1357877581.

The spelling of 21749364 in words is "twenty-one million, seven hundred forty-nine thousand, three hundred sixty-four".