21443139 has 24 divisors (see below), whose sum is σ = 31928832. Its totient is φ = 13860720.

The previous prime is 21443131. The next prime is 21443141. The reversal of 21443139 is 93134412.

It is not a de Polignac number, because 21443139 - 2³ = 21443131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21443131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68794 + ... + 69104.

It is an arithmetic number, because the mean of its divisors is an integer number (1330368).

Almost surely, 2^21443139 is an apocalyptic number.

21443139 is a deficient number, since it is larger than the sum of its proper divisors (10485693).

21443139 is a wasteful number, since it uses less digits than its factorization.

21443139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 527 (or 524 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21443139 is about 4630.6737090838. The cubic root of 21443139 is about 277.8195393864.

The spelling of 21443139 in words is "twenty-one million, four hundred forty-three thousand, one hundred thirty-nine".