21395291 has 2 divisors, whose sum is σ = 21395292. Its totient is φ = 21395290.

The previous prime is 21395261. The next prime is 21395303. The reversal of 21395291 is 19259312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21395291 - 2¹⁰ = 21394267 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21395251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10697645 + 10697646.

It is an arithmetic number, because the mean of its divisors is an integer number (10697646).

Almost surely, 2^21395291 is an apocalyptic number.

21395291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21395291 is an equidigital number, since it uses as much as digits as its factorization.

21395291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 32.

The square root of 21395291 is about 4625.5044049271. The cubic root of 21395291 is about 277.6127442748.

The spelling of 21395291 in words is "twenty-one million, three hundred ninety-five thousand, two hundred ninety-one".