21100244 has 24 divisors (see below), whose sum is σ = 40430208. Its totient is φ = 9555840.

The previous prime is 21100231. The next prime is 21100253. The reversal of 21100244 is 44200112.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 14117 + ... + 15539.

It is an arithmetic number, because the mean of its divisors is an integer number (1684592).

Almost surely, 2^21100244 is an apocalyptic number.

It is an amenable number.

21100244 is a deficient number, since it is larger than the sum of its proper divisors (19329964).

21100244 is a wasteful number, since it uses less digits than its factorization.

21100244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775 (or 1773 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21100244 is about 4593.5001904866. The cubic root of 21100244 is about 276.3307139783.

Adding to 21100244 its reverse (44200112), we get a palindrome (65300356).

The spelling of 21100244 in words is "twenty-one million, one hundred thousand, two hundred forty-four".