21405328616 has 16 divisors (see below), whose sum is σ = 45868561440. Its totient is φ = 9173712240.

The previous prime is 21405328537. The next prime is 21405328687. The reversal of 21405328616 is 61682350412.

It is a self number, because there is not a number n which added to its sum of digits gives 21405328616.

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, 191118950 + ... + 191119061.

It is an arithmetic number, because the mean of its divisors is an integer number (2866785090).

Almost surely, 2^21405328616 is an apocalyptic number.

It is an amenable number.

21405328616 is an abundant number, since it is smaller than the sum of its proper divisors (24463232824).

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

21405328616 is a wasteful number, since it uses less digits than its factorization.

21405328616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382238024 (or 382238020 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The spelling of 21405328616 in words is "twenty-one billion, four hundred five million, three hundred twenty-eight thousand, six hundred sixteen".