21231433 has 2 divisors, whose sum is σ = 21231434. Its totient is φ = 21231432.

The previous prime is 21231421. The next prime is 21231439. The reversal of 21231433 is 33413212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19123129 + 2108304 = 4373^2 + 1452^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231433 - 2⁹ = 21230921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21231433.

It is not a weakly prime, because it can be changed into another prime (21231439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615716 + 10615717.

It is an arithmetic number, because the mean of its divisors is an integer number (10615717).

Almost surely, 2^21231433 is an apocalyptic number.

It is an amenable number.

21231433 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231433 is an equidigital number, since it uses as much as digits as its factorization.

21231433 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 19.

The square root of 21231433 is about 4607.7579146479. The cubic root of 21231433 is about 276.9022188726.

Adding to 21231433 its reverse (33413212), we get a palindrome (54644645).

The spelling of 21231433 in words is "twenty-one million, two hundred thirty-one thousand, four hundred thirty-three".