21171706 has 8 divisors (see below), whose sum is σ = 31989780. Its totient is φ = 10508448.

The previous prime is 21171701. The next prime is 21171713. The reversal of 21171706 is 60717112.

It can be written as a sum of positive squares in 2 ways, for example, as 20930625 + 241081 = 4575^2 + 491^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21171706² = 896482269900872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21171701) 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, 38361 + ... + 38908.

Almost surely, 2^21171706 is an apocalyptic number.

21171706 is a deficient number, since it is larger than the sum of its proper divisors (10818074).

21171706 is a wasteful number, since it uses less digits than its factorization.

21171706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77408.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 21171706 is about 4601.2722153770. The cubic root of 21171706 is about 276.6423200782.

Adding to 21171706 its reverse (60717112), we get a palindrome (81888818).

It can be divided in two parts, 211 and 71706, that added together give a palindrome (71917).

The spelling of 21171706 in words is "twenty-one million, one hundred seventy-one thousand, seven hundred six".