21253305106666 has 32 divisors (see below), whose sum is σ = 34208666910720. Its totient is φ = 9873594788400.

The previous prime is 21253305106643. The next prime is 21253305106669. The reversal of 21253305106666 is 66660150335212.

It is not an unprimeable number, because it can be changed into a prime (21253305106669) 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, 20106226 + ... + 21136861.

It is an arithmetic number, because the mean of its divisors is an integer number (1069020840960).

Almost surely, 2^{21253305106666} is an apocalyptic number.

21253305106666 is a deficient number, since it is larger than the sum of its proper divisors (12955361804054).

21253305106666 is a wasteful number, since it uses less digits than its factorization.

21253305106666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41243370.

The product of its (nonzero) digits is 1166400, while the sum is 46.

The spelling of 21253305106666 in words is "twenty-one trillion, two hundred fifty-three billion, three hundred five million, one hundred six thousand, six hundred sixty-six".