21833257 has 2 divisors, whose sum is σ = 21833258. Its totient is φ = 21833256.

The previous prime is 21833237. The next prime is 21833263. The reversal of 21833257 is 75233812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12809241 + 9024016 = 3579^2 + 3004^2 .

It is a cyclic number.

It is not a de Polignac number, because 21833257 - 2⁷ = 21833129 is a prime.

It is a super-2 number, since 2×21833257² = 953382222456098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21833237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10916628 + 10916629.

It is an arithmetic number, because the mean of its divisors is an integer number (10916629).

Almost surely, 2^21833257 is an apocalyptic number.

It is an amenable number.

21833257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21833257 is an equidigital number, since it uses as much as digits as its factorization.

21833257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 31.

The square root of 21833257 is about 4672.6070881254. The cubic root of 21833257 is about 279.4942272631.

The spelling of 21833257 in words is "twenty-one million, eight hundred thirty-three thousand, two hundred fifty-seven".