21604742068 has 24 divisors (see below), whose sum is σ = 46533291392. Its totient is φ = 8546930784.

The previous prime is 21604742059. The next prime is 21604742119. The reversal of 21604742068 is 86024740612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21604742068.

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, 29676480 + ... + 29677207.

Almost surely, 2^21604742068 is an apocalyptic number.

21604742068 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21604742068 is an abundant number, since it is smaller than the sum of its proper divisors (24928549324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21604742068 is a wasteful number, since it uses less digits than its factorization.

21604742068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59353711 (or 59353709 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 40.

The spelling of 21604742068 in words is "twenty-one billion, six hundred four million, seven hundred forty-two thousand, sixty-eight".