21500116 has 12 divisors (see below), whose sum is σ = 41045760. Its totient is φ = 9772760.

The previous prime is 21500111. The next prime is 21500137. The reversal of 21500116 is 61100512.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21500116.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500111) 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, 244276 + ... + 244363.

It is an arithmetic number, because the mean of its divisors is an integer number (3420480).

Almost surely, 2^21500116 is an apocalyptic number.

It is an amenable number.

21500116 is a deficient number, since it is larger than the sum of its proper divisors (19545644).

21500116 is a wasteful number, since it uses less digits than its factorization.

21500116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488654 (or 488652 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 21500116 is about 4636.8217563327. The cubic root of 21500116 is about 278.0653884109.

Adding to 21500116 its reverse (61100512), we get a palindrome (82600628).

The spelling of 21500116 in words is "twenty-one million, five hundred thousand, one hundred sixteen".