21140244 has 24 divisors (see below), whose sum is σ = 54808320. Its totient is φ = 7046712.

The previous prime is 21140239. The next prime is 21140291. The reversal of 21140244 is 44204112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97764 + ... + 97979.

It is an arithmetic number, because the mean of its divisors is an integer number (2283680).

Almost surely, 2^21140244 is an apocalyptic number.

It is an amenable number.

21140244 is an abundant number, since it is smaller than the sum of its proper divisors (33668076).

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

21140244 is a wasteful number, since it uses less digits than its factorization.

21140244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195756 (or 195748 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 21140244 is about 4597.8521072344. The cubic root of 21140244 is about 276.5052183004.

Adding to 21140244 its reverse (44204112), we get a palindrome (65344356).

The spelling of 21140244 in words is "twenty-one million, one hundred forty thousand, two hundred forty-four".