21066306880 has 56 divisors (see below), whose sum is σ = 50454241992. Its totient is φ = 8377792512.

The previous prime is 21066306871. The next prime is 21066306913. The reversal of 21066306880 is 8860366012.

It can be written as a sum of positive squares in 4 ways, for example, as 5093391424 + 15972915456 = 71368^2 + 126384^2 .

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

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, 134907 + ... + 245626.

It is an arithmetic number, because the mean of its divisors is an integer number (900968607).

Almost surely, 2^21066306880 is an apocalyptic number.

21066306880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21066306880 is an abundant number, since it is smaller than the sum of its proper divisors (29387935112).

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

21066306880 is a wasteful number, since it uses less digits than its factorization.

21066306880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380723 (or 380713 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 40.

The spelling of 21066306880 in words is "twenty-one billion, sixty-six million, three hundred six thousand, eight hundred eighty".