21161203 has 16 divisors (see below), whose sum is σ = 24935680. Its totient is φ = 17581536.

The previous prime is 21161191. The next prime is 21161227. The reversal of 21161203 is 30216112.

It is a de Polignac number, because none of the positive numbers 2^k-21161203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21161603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68776 + ... + 69082.

It is an arithmetic number, because the mean of its divisors is an integer number (1558480).

Almost surely, 2^21161203 is an apocalyptic number.

21161203 is a deficient number, since it is larger than the sum of its proper divisors (3774477).

21161203 is a wasteful number, since it uses less digits than its factorization.

21161203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21161203 is about 4600.1307590111. The cubic root of 21161203 is about 276.5965663272.

Adding to 21161203 its reverse (30216112), we get a palindrome (51377315).

The spelling of 21161203 in words is "twenty-one million, one hundred sixty-one thousand, two hundred three".