21400244 has 12 divisors (see below), whose sum is σ = 38085600. Its totient is φ = 10518648.

The previous prime is 21400219. The next prime is 21400271. The reversal of 21400244 is 44200412.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 45104 + ... + 45575.

It is an arithmetic number, because the mean of its divisors is an integer number (3173800).

Almost surely, 2^21400244 is an apocalyptic number.

It is an amenable number.

21400244 is a deficient number, since it is larger than the sum of its proper divisors (16685356).

21400244 is a wasteful number, since it uses less digits than its factorization.

21400244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90742 (or 90740 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21400244 is about 4626.0397750127. The cubic root of 21400244 is about 277.6341650293.

Adding to 21400244 its reverse (44200412), we get a palindrome (65600656).

The spelling of 21400244 in words is "twenty-one million, four hundred thousand, two hundred forty-four".