21549668266 has 16 divisors (see below), whose sum is σ = 36977463360. Its totient is φ = 9226778400.

The previous prime is 21549668237. The next prime is 21549668267. The reversal of 21549668266 is 66286694512.

It is not an unprimeable number, because it can be changed into a prime (21549668267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 717571 + ... + 746998.

It is an arithmetic number, because the mean of its divisors is an integer number (2311091460).

Almost surely, 2^21549668266 is an apocalyptic number.

21549668266 is a deficient number, since it is larger than the sum of its proper divisors (15427795094).

21549668266 is a wasteful number, since it uses less digits than its factorization.

21549668266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465629.

The product of its digits is 7464960, while the sum is 55.

The spelling of 21549668266 in words is "twenty-one billion, five hundred forty-nine million, six hundred sixty-eight thousand, two hundred sixty-six".