21386923 has 2 divisors, whose sum is σ = 21386924. Its totient is φ = 21386922.

The previous prime is 21386921. The next prime is 21386947. The reversal of 21386923 is 32968312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21386923 - 2¹ = 21386921 is a prime.

It is a super-3 number, since 3×21386923³ (a number of 23 digits) contains 333 as substring.

Together with 21386921, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21386921) 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, 10693461 + 10693462.

It is an arithmetic number, because the mean of its divisors is an integer number (10693462).

Almost surely, 2^21386923 is an apocalyptic number.

21386923 is a deficient number, since it is larger than the sum of its proper divisors (1).

21386923 is an equidigital number, since it uses as much as digits as its factorization.

21386923 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21386923 is about 4624.5997664663. The cubic root of 21386923 is about 277.5765468023.

The spelling of 21386923 in words is "twenty-one million, three hundred eighty-six thousand, nine hundred twenty-three".