21640358686 has 16 divisors (see below), whose sum is σ = 32585785344. Its totient is φ = 10778501304.

The previous prime is 21640358659. The next prime is 21640358699. The reversal of 21640358686 is 68685304612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 613255 + ... + 647581.

It is an arithmetic number, because the mean of its divisors is an integer number (2036611584).

Almost surely, 2^21640358686 is an apocalyptic number.

21640358686 is a deficient number, since it is larger than the sum of its proper divisors (10945426658).

21640358686 is a wasteful number, since it uses less digits than its factorization.

21640358686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35535.

The product of its (nonzero) digits is 1658880, while the sum is 49.

The spelling of 21640358686 in words is "twenty-one billion, six hundred forty million, three hundred fifty-eight thousand, six hundred eighty-six".