21847351 has 2 divisors, whose sum is σ = 21847352. Its totient is φ = 21847350.

The previous prime is 21847349. The next prime is 21847361. The reversal of 21847351 is 15374812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21847351 - 2¹ = 21847349 is a prime.

Together with 21847349, 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 (21847361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923675 + 10923676.

It is an arithmetic number, because the mean of its divisors is an integer number (10923676).

Almost surely, 2^21847351 is an apocalyptic number.

21847351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21847351 is an equidigital number, since it uses as much as digits as its factorization.

21847351 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 31.

The square root of 21847351 is about 4674.1149964459. The cubic root of 21847351 is about 279.5543548676.

The spelling of 21847351 in words is "twenty-one million, eight hundred forty-seven thousand, three hundred fifty-one".