21331139766 has 8 divisors (see below), whose sum is σ = 42662279544. Its totient is φ = 7110379920.

The previous prime is 21331139723. The next prime is 21331139783. The reversal of 21331139766 is 66793113312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21331139766 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1777594975 + ... + 1777594986.

It is an arithmetic number, because the mean of its divisors is an integer number (5332784943).

Almost surely, 2^21331139766 is an apocalyptic number.

21331139766 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21331139766 is a wasteful number, since it uses less digits than its factorization.

21331139766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3555189966.

The product of its digits is 122472, while the sum is 42.

The spelling of 21331139766 in words is "twenty-one billion, three hundred thirty-one million, one hundred thirty-nine thousand, seven hundred sixty-six".