21213610644566 has 8 divisors (see below), whose sum is σ = 32052681777240. Its totient is φ = 10529383385488.

The previous prime is 21213610644539. The next prime is 21213610644571. The reversal of 21213610644566 is 66544601631212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21213610644566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38710968056 + ... + 38710968603.

It is an arithmetic number, because the mean of its divisors is an integer number (4006585222155).

Almost surely, 2^{21213610644566} is an apocalyptic number.

21213610644566 is a deficient number, since it is larger than the sum of its proper divisors (10839071132674).

21213610644566 is a wasteful number, since it uses less digits than its factorization.

21213610644566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77421936798.

The product of its (nonzero) digits is 1244160, while the sum is 47.

The spelling of 21213610644566 in words is "twenty-one trillion, two hundred thirteen billion, six hundred ten million, six hundred forty-four thousand, five hundred sixty-six".