21642208782 has 64 divisors (see below), whose sum is σ = 44872704000. Its totient is φ = 6955169760.

The previous prime is 21642208703. The next prime is 21642208793. The reversal of 21642208782 is 28780224612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4999503 + ... + 5003829.

It is an arithmetic number, because the mean of its divisors is an integer number (701136000).

Almost surely, 2^21642208782 is an apocalyptic number.

21642208782 is an abundant number, since it is smaller than the sum of its proper divisors (23230495218).

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

21642208782 is a wasteful number, since it uses less digits than its factorization.

21642208782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4661.

The product of its (nonzero) digits is 172032, while the sum is 42.

The spelling of 21642208782 in words is "twenty-one billion, six hundred forty-two million, two hundred eight thousand, seven hundred eighty-two".