21874843 has 2 divisors, whose sum is σ = 21874844. Its totient is φ = 21874842.

The previous prime is 21874837. The next prime is 21874891. The reversal of 21874843 is 34847812.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21874843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21874043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10937421 + 10937422.

It is an arithmetic number, because the mean of its divisors is an integer number (10937422).

Almost surely, 2^21874843 is an apocalyptic number.

21874843 is a deficient number, since it is larger than the sum of its proper divisors (1).

21874843 is an equidigital number, since it uses as much as digits as its factorization.

21874843 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43008, while the sum is 37.

The square root of 21874843 is about 4677.0549494313. The cubic root of 21874843 is about 279.6715664362.

It can be divided in two parts, 218748 and 43, that added together give a triangular number (218791 = T₆₆₁).

The spelling of 21874843 in words is "twenty-one million, eight hundred seventy-four thousand, eight hundred forty-three".