21038403 has 16 divisors (see below), whose sum is σ = 28740096. Its totient is φ = 13684320.

The previous prime is 21038393. The next prime is 21038419. The reversal of 21038403 is 30483012.

It is a happy number.

It is not a de Polignac number, because 21038403 - 2¹⁶ = 20972867 is a prime.

It is a super-2 number, since 2×21038403² = 885228801580818, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21038403.

It is not an unprimeable number, because it can be changed into a prime (21038483) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48598 + ... + 49028.

It is an arithmetic number, because the mean of its divisors is an integer number (1796256).

Almost surely, 2^21038403 is an apocalyptic number.

21038403 is a deficient number, since it is larger than the sum of its proper divisors (7701693).

21038403 is a wasteful number, since it uses less digits than its factorization.

21038403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21038403 is about 4586.7638918959. The cubic root of 21038403 is about 276.0604913619.

The spelling of 21038403 in words is "twenty-one million, thirty-eight thousand, four hundred three".