21001144 has 16 divisors (see below), whose sum is σ = 40120920. Its totient is φ = 10302240.

The previous prime is 21001121. The next prime is 21001153. The reversal of 21001144 is 44110012.

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, 24342 + ... + 25189.

Almost surely, 2^21001144 is an apocalyptic number.

It is an amenable number.

21001144 is a deficient number, since it is larger than the sum of its proper divisors (19119776).

21001144 is a wasteful number, since it uses less digits than its factorization.

21001144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49590 (or 49586 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21001144 is about 4582.7005138892. The cubic root of 21001144 is about 275.8974274031.

Adding to 21001144 its reverse (44110012), we get a palindrome (65111156).

The spelling of 21001144 in words is "twenty-one million, one thousand, one hundred forty-four".