21836869 has 2 divisors, whose sum is σ = 21836870. Its totient is φ = 21836868.

The previous prime is 21836863. The next prime is 21836879. The reversal of 21836869 is 96863812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21622500 + 214369 = 4650^2 + 463^2 .

It is a cyclic number.

It is not a de Polignac number, because 21836869 - 2³ = 21836861 is a prime.

It is a super-2 number, since 2×21836869² = 953697695446322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21836861) 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, 10918434 + 10918435.

It is an arithmetic number, because the mean of its divisors is an integer number (10918435).

Almost surely, 2^21836869 is an apocalyptic number.

It is an amenable number.

21836869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21836869 is an equidigital number, since it uses as much as digits as its factorization.

21836869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 43.

The square root of 21836869 is about 4672.9935801368. The cubic root of 21836869 is about 279.5096391870.

The spelling of 21836869 in words is "twenty-one million, eight hundred thirty-six thousand, eight hundred sixty-nine".