21203433 has 12 divisors (see below), whose sum is σ = 30899700. Its totient is φ = 14009856.

The previous prime is 21203431. The next prime is 21203459. The reversal of 21203433 is 33430212.

It can be written as a sum of positive squares in 2 ways, for example, as 9072144 + 12131289 = 3012^2 + 3483^2 .

It is not a de Polignac number, because 21203433 - 2¹ = 21203431 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21203431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9408 + ... + 11441.

It is an arithmetic number, because the mean of its divisors is an integer number (2574975).

Almost surely, 2^21203433 is an apocalyptic number.

It is an amenable number.

21203433 is a deficient number, since it is larger than the sum of its proper divisors (9696267).

21203433 is a wasteful number, since it uses less digits than its factorization.

21203433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20968 (or 20965 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 21203433 is about 4604.7185581749. The cubic root of 21203433 is about 276.7804391673.

Adding to 21203433 its reverse (33430212), we get a palindrome (54633645).

The spelling of 21203433 in words is "twenty-one million, two hundred three thousand, four hundred thirty-three".