21386293 has 2 divisors, whose sum is σ = 21386294. Its totient is φ = 21386292.

The previous prime is 21386291. The next prime is 21386329. The reversal of 21386293 is 39268312.

It is a happy number.

Together with next prime (21386329) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21362884 + 23409 = 4622^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 21386293 - 2¹ = 21386291 is a prime.

Together with 21386291, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21386291) 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, 10693146 + 10693147.

It is an arithmetic number, because the mean of its divisors is an integer number (10693147).

Almost surely, 2^21386293 is an apocalyptic number.

It is an amenable number.

21386293 is a deficient number, since it is larger than the sum of its proper divisors (1).

21386293 is an equidigital number, since it uses as much as digits as its factorization.

21386293 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 21386293 is about 4624.5316519622. The cubic root of 21386293 is about 277.5738212281.

The spelling of 21386293 in words is "twenty-one million, three hundred eighty-six thousand, two hundred ninety-three".