21050403 has 32 divisors (see below), whose sum is σ = 32762880. Its totient is φ = 11880960.

The previous prime is 21050401. The next prime is 21050413. The reversal of 21050403 is 30405012.

It is not a de Polignac number, because 21050403 - 2¹ = 21050401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21050401) 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, 87958 + ... + 88196.

It is an arithmetic number, because the mean of its divisors is an integer number (1023840).

Almost surely, 2^21050403 is an apocalyptic number.

21050403 is a deficient number, since it is larger than the sum of its proper divisors (11712477).

21050403 is a wasteful number, since it uses less digits than its factorization.

21050403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21050403 is about 4588.0718172234. The cubic root of 21050403 is about 276.1129683529.

Adding to 21050403 its reverse (30405012), we get a palindrome (51455415).

The spelling of 21050403 in words is "twenty-one million, fifty thousand, four hundred three".