21430144 has 16 divisors (see below), whose sum is σ = 42693120. Its totient is φ = 10715008.

The previous prime is 21430139. The next prime is 21430147. The reversal of 21430144 is 44103412.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21430147) 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 as a sum of consecutive naturals, namely, 83584 + ... + 83839.

It is an arithmetic number, because the mean of its divisors is an integer number (2668320).

Almost surely, 2^21430144 is an apocalyptic number.

It is an amenable number.

21430144 is a deficient number, since it is larger than the sum of its proper divisors (21262976).

21430144 is an equidigital number, since it uses as much as digits as its factorization.

21430144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167437 (or 167425 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21430144 is about 4629.2703528742. The cubic root of 21430144 is about 277.7634065217.

Adding to 21430144 its reverse (44103412), we get a palindrome (65533556).

The spelling of 21430144 in words is "twenty-one million, four hundred thirty thousand, one hundred forty-four".