21465444 has 96 divisors (see below), whose sum is σ = 67286016. Its totient is φ = 5143680.

The previous prime is 21465443. The next prime is 21465449. The reversal of 21465444 is 44456412.

It is a happy number.

It is a super-2 number, since 2×21465444² = 921530572234272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21465443) by changing a digit.

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, 11119 + ... + 12905.

It is an arithmetic number, because the mean of its divisors is an integer number (700896).

Almost surely, 2^21465444 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 21465444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33643008).

21465444 is an abundant number, since it is smaller than the sum of its proper divisors (45820572).

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

21465444 is a wasteful number, since it uses less digits than its factorization.

21465444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1825 (or 1823 counting only the distinct ones).

The product of its digits is 15360, while the sum is 30.

The square root of 21465444 is about 4633.0814799656. The cubic root of 21465444 is about 277.9158346389.

The spelling of 21465444 in words is "twenty-one million, four hundred sixty-five thousand, four hundred forty-four".