21888943 has 2 divisors, whose sum is σ = 21888944. Its totient is φ = 21888942.

The previous prime is 21888917. The next prime is 21888949. The reversal of 21888943 is 34988812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21888943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21888943.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21888949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10944471 + 10944472.

It is an arithmetic number, because the mean of its divisors is an integer number (10944472).

Almost surely, 2^21888943 is an apocalyptic number.

21888943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21888943 is an equidigital number, since it uses as much as digits as its factorization.

21888943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 110592, while the sum is 43.

The square root of 21888943 is about 4678.5620654214. The cubic root of 21888943 is about 279.7316433950.

The spelling of 21888943 in words is "twenty-one million, eight hundred eighty-eight thousand, nine hundred forty-three".