21123003 has 32 divisors (see below), whose sum is σ = 32947200. Its totient is φ = 11901600.

The previous prime is 21122971. The next prime is 21123013. The reversal of 21123003 is 30032112.

It is a happy number.

It is not a de Polignac number, because 21123003 - 2⁵ = 21122971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21123003.

It is not an unprimeable number, because it can be changed into a prime (21123013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36708 + ... + 37278.

It is an arithmetic number, because the mean of its divisors is an integer number (1029600).

Almost surely, 2^21123003 is an apocalyptic number.

21123003 is a deficient number, since it is larger than the sum of its proper divisors (11824197).

21123003 is a wasteful number, since it uses less digits than its factorization.

21123003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21123003 is about 4595.9768276178. The cubic root of 21123003 is about 276.4300295903.

Adding to 21123003 its reverse (30032112), we get a palindrome (51155115).

It can be divided in two parts, 2112 and 3003, that added together give a palindrome (5115).

The spelling of 21123003 in words is "twenty-one million, one hundred twenty-three thousand, three".