21593191 has 2 divisors, whose sum is σ = 21593192. Its totient is φ = 21593190.

The previous prime is 21593189. The next prime is 21593203. The reversal of 21593191 is 19139512.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21593191 - 2¹ = 21593189 is a prime.

Together with 21593189, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21593141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10796595 + 10796596.

It is an arithmetic number, because the mean of its divisors is an integer number (10796596).

Almost surely, 2^21593191 is an apocalyptic number.

21593191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21593191 is an equidigital number, since it uses as much as digits as its factorization.

21593191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2430, while the sum is 31.

The square root of 21593191 is about 4646.8474259437. The cubic root of 21593191 is about 278.4660634428.

The spelling of 21593191 in words is "twenty-one million, five hundred ninety-three thousand, one hundred ninety-one".