21568917266 has 16 divisors (see below), whose sum is σ = 35075943000. Its totient is φ = 9888071808.

The previous prime is 21568917241. The next prime is 21568917269. The reversal of 21568917266 is 66271986512.

It can be written as a sum of positive squares in 4 ways, for example, as 10831605625 + 10737311641 = 104075^2 + 103621^2 .

It is not an unprimeable number, because it can be changed into a prime (21568917269) 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, 2779931 + ... + 2787678.

Almost surely, 2^21568917266 is an apocalyptic number.

21568917266 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21568917266 is a deficient number, since it is larger than the sum of its proper divisors (13507025734).

21568917266 is a wasteful number, since it uses less digits than its factorization.

21568917266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5567773.

The product of its digits is 2177280, while the sum is 53.

The spelling of 21568917266 in words is "twenty-one billion, five hundred sixty-eight million, nine hundred seventeen thousand, two hundred sixty-six".