21144903 has 16 divisors (see below), whose sum is σ = 30750720. Its totient is φ = 12845664.

The previous prime is 21144901. The next prime is 21144919. The reversal of 21144903 is 30944112.

It is not a de Polignac number, because 21144903 - 2¹ = 21144901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144901) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 351 + ... + 6512.

It is an arithmetic number, because the mean of its divisors is an integer number (1921920).

Almost surely, 2^21144903 is an apocalyptic number.

21144903 is a deficient number, since it is larger than the sum of its proper divisors (9605817).

21144903 is a wasteful number, since it uses less digits than its factorization.

21144903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6958.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21144903 is about 4598.3587289380. The cubic root of 21144903 is about 276.5255293745.

The spelling of 21144903 in words is "twenty-one million, one hundred forty-four thousand, nine hundred three".