21311444 has 24 divisors (see below), whose sum is σ = 46498368. Its totient is φ = 8303040.

The previous prime is 21311443. The next prime is 21311447. The reversal of 21311444 is 44411312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311443) 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 7 ways as a sum of consecutive naturals, for example, 34289 + ... + 34904.

It is an arithmetic number, because the mean of its divisors is an integer number (1937432).

Almost surely, 2^21311444 is an apocalyptic number.

It is an amenable number.

21311444 is an abundant number, since it is smaller than the sum of its proper divisors (25186924).

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

21311444 is a wasteful number, since it uses less digits than its factorization.

21311444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69215 (or 69213 counting only the distinct ones).

The product of its digits is 384, while the sum is 20.

The square root of 21311444 is about 4616.4319555258. The cubic root of 21311444 is about 277.2496196781.

Adding to 21311444 its reverse (44411312), we get a palindrome (65722756).

The spelling of 21311444 in words is "twenty-one million, three hundred eleven thousand, four hundred forty-four".