21771566567268 has 24 divisors (see below), whose sum is σ = 58057510846272. Its totient is φ = 6220447590624.

The previous prime is 21771566567239. The next prime is 21771566567297. The reversal of 21771566567268 is 86276566517712.

It is an interprime number because it is at equal distance from previous prime (21771566567239) and next prime (21771566567297).

It is a super-2 number, since 2×21771566567268² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 129592658055 + ... + 129592658222.

It is an arithmetic number, because the mean of its divisors is an integer number (2419062951928).

Almost surely, 2^{21771566567268} is an apocalyptic number.

21771566567268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21771566567268 is an abundant number, since it is smaller than the sum of its proper divisors (36285944279004).

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

21771566567268 is a wasteful number, since it uses less digits than its factorization.

21771566567268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259185316291 (or 259185316289 counting only the distinct ones).

The product of its digits is 355622400, while the sum is 69.

The spelling of 21771566567268 in words is "twenty-one trillion, seven hundred seventy-one billion, five hundred sixty-six million, five hundred sixty-seven thousand, two hundred sixty-eight".