21748351 has 2 divisors, whose sum is σ = 21748352. Its totient is φ = 21748350.

The previous prime is 21748333. The next prime is 21748361. The reversal of 21748351 is 15384712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21748351 - 2⁹ = 21747839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21748361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10874175 + 10874176.

It is an arithmetic number, because the mean of its divisors is an integer number (10874176).

Almost surely, 2^21748351 is an apocalyptic number.

21748351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21748351 is an equidigital number, since it uses as much as digits as its factorization.

21748351 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 21748351 is about 4663.5127318364. The cubic root of 21748351 is about 279.1314540077.

The spelling of 21748351 in words is "twenty-one million, seven hundred forty-eight thousand, three hundred fifty-one".