21105025266 has 32 divisors (see below), whose sum is σ = 45638123328. Its totient is φ = 6467976000.

The previous prime is 21105025261. The next prime is 21105025303. The reversal of 21105025266 is 66252050112.

It is not an unprimeable number, because it can be changed into a prime (21105025261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 519421 + ... + 558576.

It is an arithmetic number, because the mean of its divisors is an integer number (1426191354).

Almost surely, 2^21105025266 is an apocalyptic number.

21105025266 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21105025266 is an abundant number, since it is smaller than the sum of its proper divisors (24533098062).

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

21105025266 is a wasteful number, since it uses less digits than its factorization.

21105025266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078266.

The product of its (nonzero) digits is 7200, while the sum is 30.

Adding to 21105025266 its reverse (66252050112), we get a palindrome (87357075378).

The spelling of 21105025266 in words is "twenty-one billion, one hundred five million, twenty-five thousand, two hundred sixty-six".