21116610 has 24 divisors (see below), whose sum is σ = 54903420. Its totient is φ = 5631072.

The previous prime is 21116597. The next prime is 21116629. The reversal of 21116610 is 1661112.

21116610 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 661 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20602521 + 514089 = 4539^2 + 717^2 .

It is a super-2 number, since 2×21116610² = 891822435784200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 117225 + ... + 117404.

Almost surely, 2^21116610 is an apocalyptic number.

21116610 is an abundant number, since it is smaller than the sum of its proper divisors (33786810).

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

21116610 is a wasteful number, since it uses less digits than its factorization.

21116610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234642 (or 234639 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21116610 is about 4595.2812753954. The cubic root of 21116610 is about 276.4021390563.

Adding to 21116610 its reverse (1661112), we get a palindrome (22777722).

The spelling of 21116610 in words is "twenty-one million, one hundred sixteen thousand, six hundred ten".