21021116 has 12 divisors (see below), whose sum is σ = 37336488. Its totient is φ = 10353552.

The previous prime is 21021107. The next prime is 21021127. The reversal of 21021116 is 61112012.

It is a self number, because there is not a number n which added to its sum of digits gives 21021116.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38951 + ... + 39486.

It is an arithmetic number, because the mean of its divisors is an integer number (3111374).

Almost surely, 2^21021116 is an apocalyptic number.

It is an amenable number.

21021116 is a deficient number, since it is larger than the sum of its proper divisors (16315372).

21021116 is a wasteful number, since it uses less digits than its factorization.

21021116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78508 (or 78506 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 21021116 is about 4584.8790605642. The cubic root of 21021116 is about 275.9848587927.

Adding to 21021116 its reverse (61112012), we get a palindrome (82133128).

The spelling of 21021116 in words is "twenty-one million, twenty-one thousand, one hundred sixteen".