21408780550 has 12 divisors (see below), whose sum is σ = 39820331916. Its totient is φ = 8563512200.

The previous prime is 21408780529. The next prime is 21408780583. The reversal of 21408780550 is 5508780412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 214087756 + ... + 214087855.

It is an arithmetic number, because the mean of its divisors is an integer number (3318360993).

Almost surely, 2^21408780550 is an apocalyptic number.

21408780550 is a deficient number, since it is larger than the sum of its proper divisors (18411551366).

21408780550 is a wasteful number, since it uses less digits than its factorization.

21408780550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428175623 (or 428175618 counting only the distinct ones).

The product of its (nonzero) digits is 89600, while the sum is 40.

The spelling of 21408780550 in words is "twenty-one billion, four hundred eight million, seven hundred eighty thousand, five hundred fifty".