21787225166 has 16 divisors (see below), whose sum is σ = 37351481856. Its totient is φ = 9336893976.

The previous prime is 21787225123. The next prime is 21787225169. The reversal of 21787225166 is 66152278712.

It is a self number, because there is not a number n which added to its sum of digits gives 21787225166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21787225169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 404855 + ... + 455501.

It is an arithmetic number, because the mean of its divisors is an integer number (2334467616).

Almost surely, 2^21787225166 is an apocalyptic number.

21787225166 is a deficient number, since it is larger than the sum of its proper divisors (15564256690).

21787225166 is a wasteful number, since it uses less digits than its factorization.

21787225166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81383.

The product of its digits is 564480, while the sum is 47.

The spelling of 21787225166 in words is "twenty-one billion, seven hundred eighty-seven million, two hundred twenty-five thousand, one hundred sixty-six".