21444501 has 16 divisors (see below), whose sum is σ = 30920960. Its totient is φ = 13141440.

The previous prime is 21444499. The next prime is 21444541. The reversal of 21444501 is 10544412.

It is a happy number.

It is not a de Polignac number, because 21444501 - 2¹ = 21444499 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444541) 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, 9555 + ... + 11583.

It is an arithmetic number, because the mean of its divisors is an integer number (1932560).

Almost surely, 2^21444501 is an apocalyptic number.

It is an amenable number.

21444501 is a deficient number, since it is larger than the sum of its proper divisors (9476459).

21444501 is a wasteful number, since it uses less digits than its factorization.

21444501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2316.

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 21444501 is about 4630.8207695829. The cubic root of 21444501 is about 277.8254213330.

Adding to 21444501 its reverse (10544412), we get a palindrome (31988913).

It can be divided in two parts, 21444 and 501, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21444501 in words is "twenty-one million, four hundred forty-four thousand, five hundred one".