21836939 has 2 divisors, whose sum is σ = 21836940. Its totient is φ = 21836938.

The previous prime is 21836921. The next prime is 21836953. The reversal of 21836939 is 93963812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21836939 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21836896 and 21836905.

It is not a weakly prime, because it can be changed into another prime (21833939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10918469 + 10918470.

It is an arithmetic number, because the mean of its divisors is an integer number (10918470).

Almost surely, 2^21836939 is an apocalyptic number.

21836939 is a deficient number, since it is larger than the sum of its proper divisors (1).

21836939 is an equidigital number, since it uses as much as digits as its factorization.

21836939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 41.

The square root of 21836939 is about 4673.0010699763. The cubic root of 21836939 is about 279.5099378509.

The spelling of 21836939 in words is "twenty-one million, eight hundred thirty-six thousand, nine hundred thirty-nine".