21982351 has 2 divisors, whose sum is σ = 21982352. Its totient is φ = 21982350.

The previous prime is 21982339. The next prime is 21982361. The reversal of 21982351 is 15328912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21982351 - 2²¹ = 19885199 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21982361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10991175 + 10991176.

It is an arithmetic number, because the mean of its divisors is an integer number (10991176).

Almost surely, 2^21982351 is an apocalyptic number.

21982351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21982351 is an equidigital number, since it uses as much as digits as its factorization.

21982351 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 21982351 is about 4688.5339926250. The cubic root of 21982351 is about 280.1289839409.

The spelling of 21982351 in words is "twenty-one million, nine hundred eighty-two thousand, three hundred fifty-one".