21667787776 has 88 divisors (see below), whose sum is σ = 44854519040. Its totient is φ = 10450944000.

The previous prime is 21667787747. The next prime is 21667787833. The reversal of 21667787776 is 67778776612.

It is a Harshad number since it is a multiple of its sum of digits (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12030076 + ... + 12031876.

Almost surely, 2^21667787776 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21667787776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22427259520).

21667787776 is an abundant number, since it is smaller than the sum of its proper divisors (23186731264).

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

21667787776 is a wasteful number, since it uses less digits than its factorization.

21667787776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2231 (or 2213 counting only the distinct ones).

The product of its digits is 58084992, while the sum is 64.

The spelling of 21667787776 in words is "twenty-one billion, six hundred sixty-seven million, seven hundred eighty-seven thousand, seven hundred seventy-six".