21871039 has 2 divisors, whose sum is σ = 21871040. Its totient is φ = 21871038.

The previous prime is 21870997. The next prime is 21871043. The reversal of 21871039 is 93017812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21871039 - 2¹⁷ = 21739967 is a prime.

It is a Chen prime.

It is a plaindrome in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 21871039.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21871049) 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, 10935519 + 10935520.

It is an arithmetic number, because the mean of its divisors is an integer number (10935520).

Almost surely, 2^21871039 is an apocalyptic number.

21871039 is a deficient number, since it is larger than the sum of its proper divisors (1).

21871039 is an equidigital number, since it uses as much as digits as its factorization.

21871039 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21871039 is about 4676.6482655851. The cubic root of 21871039 is about 279.6553540179.

The spelling of 21871039 in words is "twenty-one million, eight hundred seventy-one thousand, thirty-nine".