21761364566 has 4 divisors (see below), whose sum is σ = 32642046852. Its totient is φ = 10880682282.

The previous prime is 21761364557. The next prime is 21761364643. The reversal of 21761364566 is 66546316712.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21761364566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5440341140 + ... + 5440341143.

It is an arithmetic number, because the mean of its divisors is an integer number (8160511713).

Almost surely, 2^21761364566 is an apocalyptic number.

21761364566 is a deficient number, since it is larger than the sum of its proper divisors (10880682286).

21761364566 is a wasteful number, since it uses less digits than its factorization.

21761364566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10880682285.

The product of its digits is 1088640, while the sum is 47.

The spelling of 21761364566 in words is "twenty-one billion, seven hundred sixty-one million, three hundred sixty-four thousand, five hundred sixty-six".