21083403 has 18 divisors (see below), whose sum is σ = 31027836. Its totient is φ = 12724800.

The previous prime is 21083399. The next prime is 21083429. The reversal of 21083403 is 30438012.

It is a happy number.

It is not a de Polignac number, because 21083403 - 2² = 21083399 is a prime.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21083403.

It is not an unprimeable number, because it can be changed into a prime (21083443) 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 17 ways as a sum of consecutive naturals, for example, 87363 + ... + 87603.

Almost surely, 2^21083403 is an apocalyptic number.

21083403 is a deficient number, since it is larger than the sum of its proper divisors (9944433).

21083403 is an equidigital number, since it uses as much as digits as its factorization.

21083403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507 (or 255 counting only the distinct ones).

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

The square root of 21083403 is about 4591.6666908651. Note that the first 4 decimals coincide. The cubic root of 21083403 is about 276.2571773215.

The spelling of 21083403 in words is "twenty-one million, eighty-three thousand, four hundred three".