21210433 has 2 divisors, whose sum is σ = 21210434. Its totient is φ = 21210432.

The previous prime is 21210389. The next prime is 21210461. The reversal of 21210433 is 33401212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14799409 + 6411024 = 3847^2 + 2532^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210433 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605216 + 10605217.

It is an arithmetic number, because the mean of its divisors is an integer number (10605217).

Almost surely, 2^21210433 is an apocalyptic number.

It is an amenable number.

21210433 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210433 is an equidigital number, since it uses as much as digits as its factorization.

21210433 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21210433 is about 4605.4785853373. The cubic root of 21210433 is about 276.8108941398.

Adding to 21210433 its reverse (33401212), we get a palindrome (54611645).

The spelling of 21210433 in words is "twenty-one million, two hundred ten thousand, four hundred thirty-three".