21836123 has 2 divisors, whose sum is σ = 21836124. Its totient is φ = 21836122.

The previous prime is 21836117. The next prime is 21836147. The reversal of 21836123 is 32163812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21836123 - 2⁴ = 21836107 is a prime.

It is a super-2 number, since 2×21836123² = 953632535342258, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21836092 and 21836101.

It is not a weakly prime, because it can be changed into another prime (21836323) 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, 10918061 + 10918062.

It is an arithmetic number, because the mean of its divisors is an integer number (10918062).

Almost surely, 2^21836123 is an apocalyptic number.

21836123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21836123 is an equidigital number, since it uses as much as digits as its factorization.

21836123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 26.

The square root of 21836123 is about 4672.9137591015. The cubic root of 21836123 is about 279.5064562434.

Adding to 21836123 its reverse (32163812), we get a palindrome (53999935).

The spelling of 21836123 in words is "twenty-one million, eight hundred thirty-six thousand, one hundred twenty-three".