21615544643206 has 16 divisors (see below), whose sum is σ = 32493853555200. Its totient is φ = 10784260855368.

The previous prime is 21615544643023. The next prime is 21615544643233. The reversal of 21615544643206 is 60234644551612.

It is a self number, because there is not a number n which added to its sum of digits gives 21615544643206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76493805 + ... + 76775863.

It is an arithmetic number, because the mean of its divisors is an integer number (2030865847200).

Almost surely, 2^{21615544643206} is an apocalyptic number.

21615544643206 is a deficient number, since it is larger than the sum of its proper divisors (10878308911994).

21615544643206 is a wasteful number, since it uses less digits than its factorization.

21615544643206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365283.

The product of its (nonzero) digits is 4147200, while the sum is 49.

The spelling of 21615544643206 in words is "twenty-one trillion, six hundred fifteen billion, five hundred forty-four million, six hundred forty-three thousand, two hundred six".