21016443 has 12 divisors (see below), whose sum is σ = 32597160. Its totient is φ = 12009312.

The previous prime is 21016441. The next prime is 21016459. The reversal of 21016443 is 34461012.

It is not a de Polignac number, because 21016443 - 2¹ = 21016441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21016441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71338 + ... + 71631.

It is an arithmetic number, because the mean of its divisors is an integer number (2716430).

Almost surely, 2^21016443 is an apocalyptic number.

21016443 is a deficient number, since it is larger than the sum of its proper divisors (11580717).

21016443 is a wasteful number, since it uses less digits than its factorization.

21016443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142986 (or 142979 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21016443 is about 4584.3694222870. The cubic root of 21016443 is about 275.9644067732.

Adding to 21016443 its reverse (34461012), we get a palindrome (55477455).

It can be divided in two parts, 210 and 16443, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 21016443 in words is "twenty-one million, sixteen thousand, four hundred forty-three".