21334644 has 96 divisors (see below), whose sum is σ = 60009600. Its totient is φ = 6531840.

The previous prime is 21334631. The next prime is 21334657. The reversal of 21334644 is 44643312.

21334644 is a `hidden beast` number, since 2 + 13 + 3 + 4 + 644 = 666.

It is an interprime number because it is at equal distance from previous prime (21334631) and next prime (21334657).

It is a Harshad number since it is a multiple of its sum of digits (27).

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 75784 + ... + 76064.

It is an arithmetic number, because the mean of its divisors is an integer number (625100).

Almost surely, 2^21334644 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 21334644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30004800).

21334644 is an abundant number, since it is smaller than the sum of its proper divisors (38674956).

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

21334644 is a wasteful number, since it uses less digits than its factorization.

21334644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 342 counting only the distinct ones).

The product of its digits is 6912, while the sum is 27.

The square root of 21334644 is about 4618.9440351665. The cubic root of 21334644 is about 277.3501894084.

Adding to 21334644 its reverse (44643312), we get a palindrome (65977956).

The spelling of 21334644 in words is "twenty-one million, three hundred thirty-four thousand, six hundred forty-four".