21261268900766 has 4 divisors (see below), whose sum is σ = 31891903351152. Its totient is φ = 10630634450382.

The previous prime is 21261268900741. The next prime is 21261268900777. The reversal of 21261268900766 is 66700986216212.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5315317225190 + ... + 5315317225193.

It is an arithmetic number, because the mean of its divisors is an integer number (7972975837788).

Almost surely, 2^{21261268900766} is an apocalyptic number.

21261268900766 is a deficient number, since it is larger than the sum of its proper divisors (10630634450386).

21261268900766 is a wasteful number, since it uses less digits than its factorization.

21261268900766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10630634450385.

The product of its (nonzero) digits is 5225472, while the sum is 56.

The spelling of 21261268900766 in words is "twenty-one trillion, two hundred sixty-one billion, two hundred sixty-eight million, nine hundred thousand, seven hundred sixty-six".