21233869 has 2 divisors, whose sum is σ = 21233870. Its totient is φ = 21233868.

The previous prime is 21233851. The next prime is 21233879. The reversal of 21233869 is 96833212.

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., 19245769 + 1988100 = 4387^2 + 1410^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21233869 is a prime.

It is a super-2 number, since 2×21233869² = 901754385418322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21233879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616934 + 10616935.

It is an arithmetic number, because the mean of its divisors is an integer number (10616935).

Almost surely, 2^21233869 is an apocalyptic number.

It is an amenable number.

21233869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233869 is an equidigital number, since it uses as much as digits as its factorization.

21233869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 34.

The square root of 21233869 is about 4608.0222438699. The cubic root of 21233869 is about 276.9128086431.

The spelling of 21233869 in words is "twenty-one million, two hundred thirty-three thousand, eight hundred sixty-nine".