21066668780 has 12 divisors (see below), whose sum is σ = 44240004480. Its totient is φ = 8426667504.

The previous prime is 21066668771. The next prime is 21066668789. The reversal of 21066668780 is 8786666012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21066668771) and next prime (21066668789).

It is not an unprimeable number, because it can be changed into a prime (21066668789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526666700 + ... + 526666739.

It is an arithmetic number, because the mean of its divisors is an integer number (3686667040).

Almost surely, 2^21066668780 is an apocalyptic number.

21066668780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21066668780 is an abundant number, since it is smaller than the sum of its proper divisors (23173335700).

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

21066668780 is a wasteful number, since it uses less digits than its factorization.

21066668780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1053333448 (or 1053333446 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 50.

The spelling of 21066668780 in words is "twenty-one billion, sixty-six million, six hundred sixty-eight thousand, seven hundred eighty".