21616172 has 12 divisors (see below), whose sum is σ = 37882656. Its totient is φ = 10792560.

The previous prime is 21616171. The next prime is 21616187. The reversal of 21616172 is 27161612.

It is not an unprimeable number, because it can be changed into a prime (21616171) 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, 404 + ... + 6587.

It is an arithmetic number, because the mean of its divisors is an integer number (3156888).

Almost surely, 2^21616172 is an apocalyptic number.

It is an amenable number.

21616172 is a deficient number, since it is larger than the sum of its proper divisors (16266484).

21616172 is a wasteful number, since it uses less digits than its factorization.

21616172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7768 (or 7766 counting only the distinct ones).

The product of its digits is 1008, while the sum is 26.

The square root of 21616172 is about 4649.3195201018. The cubic root of 21616172 is about 278.5648161732.

Adding to 21616172 its reverse (27161612), we get a palindrome (48777784).

It can be divided in two parts, 2161617 and 2, that multiplied together give a palindrome (4323234).

The spelling of 21616172 in words is "twenty-one million, six hundred sixteen thousand, one hundred seventy-two".