21610165266 has 24 divisors (see below), whose sum is σ = 46897690320. Its totient is φ = 7191747576.

The previous prime is 21610165259. The next prime is 21610165331. The reversal of 21610165266 is 66256101612.

21610165266 is a `hidden beast` number, since 2 + 1 + 610 + 16 + 5 + 26 + 6 = 666.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21610165266.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 958620 + ... + 980903.

It is an arithmetic number, because the mean of its divisors is an integer number (1954070430).

Almost surely, 2^21610165266 is an apocalyptic number.

21610165266 is an abundant number, since it is smaller than the sum of its proper divisors (25287525054).

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

21610165266 is a wasteful number, since it uses less digits than its factorization.

21610165266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940150 (or 1940147 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

Adding to 21610165266 its reverse (66256101612), we get a palindrome (87866266878).

The spelling of 21610165266 in words is "twenty-one billion, six hundred ten million, one hundred sixty-five thousand, two hundred sixty-six".