21598409686 has 16 divisors (see below), whose sum is σ = 37317390336. Its totient is φ = 9183575016.

The previous prime is 21598409681. The next prime is 21598409687. The reversal of 21598409686 is 68690489512.

It is a self number, because there is not a number n which added to its sum of digits gives 21598409686.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21598409681) by changing a digit.

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, 6072016 + ... + 6075571.

It is an arithmetic number, because the mean of its divisors is an integer number (2332336896).

Almost surely, 2^21598409686 is an apocalyptic number.

21598409686 is a deficient number, since it is larger than the sum of its proper divisors (15718980650).

21598409686 is a wasteful number, since it uses less digits than its factorization.

21598409686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12147723.

The product of its (nonzero) digits is 7464960, while the sum is 58.

The spelling of 21598409686 in words is "twenty-one billion, five hundred ninety-eight million, four hundred nine thousand, six hundred eighty-six".