21266371368 has 256 divisors, whose sum is σ = 66398745600. Its totient is φ = 6250970880.

The previous prime is 21266371367. The next prime is 21266371369. The reversal of 21266371368 is 86317366212.

21266371368 is a `hidden beast` number, since 2 + 1 + 2 + 6 + 637 + 1 + 3 + 6 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21266371367) and next prime (21266371369).

It is not an unprimeable number, because it can be changed into a prime (21266371367) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16652746 + ... + 16654022.

It is an arithmetic number, because the mean of its divisors is an integer number (259370100).

Almost surely, 2^21266371368 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21266371368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33199372800).

21266371368 is an abundant number, since it is smaller than the sum of its proper divisors (45132374232).

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

21266371368 is a wasteful number, since it uses less digits than its factorization.

21266371368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1509 (or 1499 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The spelling of 21266371368 in words is "twenty-one billion, two hundred sixty-six million, three hundred seventy-one thousand, three hundred sixty-eight".