21311791226856 has 48 divisors (see below), whose sum is σ = 62159391081060. Its totient is φ = 6557474223360.

The previous prime is 21311791226851. The next prime is 21311791226899. The reversal of 21311791226856 is 65862219711312.

21311791226856 is a `hidden beast` number, since 2 + 1 + 311 + 7 + 9 + 12 + 268 + 56 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 16220224624356 + 5091566602500 = 4027434^2 + 2256450^2 .

It is not an unprimeable number, because it can be changed into a prime (21311791226851) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11384502925 + ... + 11384504796.

Almost surely, 2^{21311791226856} is an apocalyptic number.

21311791226856 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21311791226856 is an abundant number, since it is smaller than the sum of its proper divisors (40847599854204).

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

21311791226856 is a wasteful number, since it uses less digits than its factorization.

21311791226856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22769007746 (or 22769007739 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 21311791226856 in words is "twenty-one trillion, three hundred eleven billion, seven hundred ninety-one million, two hundred twenty-six thousand, eight hundred fifty-six".