21444730 has 32 divisors (see below), whose sum is σ = 41342400. Its totient is φ = 7984512.

The previous prime is 21444727. The next prime is 21444739. The reversal of 21444730 is 3744412.

It is a junction number, because it is equal to n+sod(n) for n = 21444695 and 21444704.

It is not an unprimeable number, because it can be changed into a prime (21444739) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 10254 + ... + 12166.

It is an arithmetic number, because the mean of its divisors is an integer number (1291950).

Almost surely, 2^21444730 is an apocalyptic number.

21444730 is a deficient number, since it is larger than the sum of its proper divisors (19897670).

21444730 is a wasteful number, since it uses less digits than its factorization.

21444730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1998.

The product of its (nonzero) digits is 2688, while the sum is 25.

The square root of 21444730 is about 4630.8454951553. The cubic root of 21444730 is about 277.8264102703.

It can be divided in two parts, 214 and 44730, that added together give a palindrome (44944).

The spelling of 21444730 in words is "twenty-one million, four hundred forty-four thousand, seven hundred thirty".