21705016 has 8 divisors (see below), whose sum is σ = 40696920. Its totient is φ = 10852504.

The previous prime is 21705007. The next prime is 21705029. The reversal of 21705016 is 61050712.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21705016² = 942215439120512, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1356556 + ... + 1356571.

It is an arithmetic number, because the mean of its divisors is an integer number (5087115).

Almost surely, 2^21705016 is an apocalyptic number.

It is an amenable number.

21705016 is a deficient number, since it is larger than the sum of its proper divisors (18991904).

21705016 is a wasteful number, since it uses less digits than its factorization.

21705016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2713133 (or 2713129 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 21705016 is about 4658.8642392755. The cubic root of 21705016 is about 278.9459348911.

Adding to 21705016 its reverse (61050712), we get a palindrome (82755728).

The spelling of 21705016 in words is "twenty-one million, seven hundred five thousand, sixteen".