21207116 has 24 divisors (see below), whose sum is σ = 44647680. Its totient is φ = 8610192.

The previous prime is 21207107. The next prime is 21207133. The reversal of 21207116 is 61170212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19400 + ... + 20463.

It is an arithmetic number, because the mean of its divisors is an integer number (1860320).

Almost surely, 2^21207116 is an apocalyptic number.

It is an amenable number.

21207116 is an abundant number, since it is smaller than the sum of its proper divisors (23440564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21207116 is a wasteful number, since it uses less digits than its factorization.

21207116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39893 (or 39891 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21207116 is about 4605.1184566741. The cubic root of 21207116 is about 276.7964636689.

Adding to 21207116 its reverse (61170212), we get a palindrome (82377328).

The spelling of 21207116 in words is "twenty-one million, two hundred seven thousand, one hundred sixteen".