21055666142740 has 12 divisors (see below), whose sum is σ = 44216898899796. Its totient is φ = 8422266457088.

The previous prime is 21055666142729. The next prime is 21055666142741. The reversal of 21055666142740 is 4724166655012.

It can be written as a sum of positive squares in 2 ways, for example, as 12515080727556 + 8540585415184 = 3537666^2 + 2922428^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055666142741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 526391653549 + ... + 526391653588.

It is an arithmetic number, because the mean of its divisors is an integer number (3684741574983).

Almost surely, 2^{21055666142740} is an apocalyptic number.

21055666142740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21055666142740 is an abundant number, since it is smaller than the sum of its proper divisors (23161232757056).

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

21055666142740 is a wasteful number, since it uses less digits than its factorization.

21055666142740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1052783307146 (or 1052783307144 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 49.

The spelling of 21055666142740 in words is "twenty-one trillion, fifty-five billion, six hundred sixty-six million, one hundred forty-two thousand, seven hundred forty".