21704071 has 4 divisors (see below), whose sum is σ = 21722032. Its totient is φ = 21686112.

The previous prime is 21704069. The next prime is 21704077. The reversal of 21704071 is 17040712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21704071 - 2¹ = 21704069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21704077) 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 in 3 ways as a sum of consecutive naturals, for example, 7026 + ... + 9631.

It is an arithmetic number, because the mean of its divisors is an integer number (5430508).

Almost surely, 2^21704071 is an apocalyptic number.

21704071 is a deficient number, since it is larger than the sum of its proper divisors (17961).

21704071 is a wasteful number, since it uses less digits than its factorization.

21704071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17960.

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 21704071 is about 4658.7628186032. The cubic root of 21704071 is about 278.9418865529.

Adding to 21704071 its reverse (17040712), we get a palindrome (38744783).

It can be divided in two parts, 2170 and 4071, that added together give a square (6241 = 79²).

The spelling of 21704071 in words is "twenty-one million, seven hundred four thousand, seventy-one".