21292393 has 2 divisors, whose sum is σ = 21292394. Its totient is φ = 21292392.

The previous prime is 21292391. The next prime is 21292417. The reversal of 21292393 is 39329212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17081689 + 4210704 = 4133^2 + 2052^2 .

It is a cyclic number.

It is not a de Polignac number, because 21292393 - 2¹ = 21292391 is a prime.

Together with 21292391, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21292391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646196 + 10646197.

It is an arithmetic number, because the mean of its divisors is an integer number (10646197).

Almost surely, 2^21292393 is an apocalyptic number.

It is an amenable number.

21292393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21292393 is an equidigital number, since it uses as much as digits as its factorization.

21292393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 31.

The square root of 21292393 is about 4614.3681040853. The cubic root of 21292393 is about 277.1669808673.

Adding to 21292393 its product of digits (5832), we get a square (21298225 = 4615²).

The spelling of 21292393 in words is "twenty-one million, two hundred ninety-two thousand, three hundred ninety-three".