21706141 has 4 divisors (see below), whose sum is σ = 21721212. Its totient is φ = 21691072.

The previous prime is 21706133. The next prime is 21706177. The reversal of 21706141 is 14160712.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19316025 + 2390116 = 4395^2 + 1546^2 .

It is a cyclic number.

It is not a de Polignac number, because 21706141 - 2³ = 21706133 is a prime.

It is a super-2 number, since 2×21706141² = 942313114223762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5116 + ... + 8341.

It is an arithmetic number, because the mean of its divisors is an integer number (5430303).

Almost surely, 2^21706141 is an apocalyptic number.

It is an amenable number.

21706141 is a deficient number, since it is larger than the sum of its proper divisors (15071).

21706141 is a wasteful number, since it uses less digits than its factorization.

21706141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15070.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21706141 is about 4658.9849752924. The cubic root of 21706141 is about 278.9507541881.

Adding to 21706141 its reverse (14160712), we get a palindrome (35866853).

The spelling of 21706141 in words is "twenty-one million, seven hundred six thousand, one hundred forty-one".