21836957 has 2 divisors, whose sum is σ = 21836958. Its totient is φ = 21836956.

The previous prime is 21836953. The next prime is 21836981. The reversal of 21836957 is 75963812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21659716 + 177241 = 4654^2 + 421^2 .

It is a cyclic number.

It is not a de Polignac number, because 21836957 - 2² = 21836953 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21836953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10918478 + 10918479.

It is an arithmetic number, because the mean of its divisors is an integer number (10918479).

Almost surely, 2^21836957 is an apocalyptic number.

It is an amenable number.

21836957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21836957 is an equidigital number, since it uses as much as digits as its factorization.

21836957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 41.

The square root of 21836957 is about 4673.0029959331. The cubic root of 21836957 is about 279.5100146501.

The spelling of 21836957 in words is "twenty-one million, eight hundred thirty-six thousand, nine hundred fifty-seven".