21023044 has 48 divisors (see below), whose sum is σ = 45337600. Its totient is φ = 8328096.

The previous prime is 21023017. The next prime is 21023047. The reversal of 21023044 is 44032012.

21023044 = T₁₀₄ + T₁₀₅ + ... + T₅₀₂.

It is not an unprimeable number, because it can be changed into a prime (21023047) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22417 + ... + 23335.

Almost surely, 2^21023044 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 21023044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22668800).

21023044 is an abundant number, since it is smaller than the sum of its proper divisors (24314556).

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

21023044 is a wasteful number, since it uses less digits than its factorization.

21023044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 992 (or 990 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21023044 is about 4585.0893121072. The cubic root of 21023044 is about 275.9932960634.

Adding to 21023044 its reverse (44032012), we get a palindrome (65055056).

The spelling of 21023044 in words is "twenty-one million, twenty-three thousand, forty-four".