20071812217779 has 72 divisors (see below), whose sum is σ = 34333994560320. Its totient is φ = 11263286799072.

The previous prime is 20071812217739. The next prime is 20071812217789. The reversal of 20071812217779 is 97771221817002.

It is a happy number.

20071812217779 is a `hidden beast` number, since 200 + 7 + 1 + 81 + 221 + 77 + 79 = 666.

It is not a de Polignac number, because 20071812217779 - 2⁷ = 20071812217651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20071812217739) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 24232692 + ... + 25047294.

It is an arithmetic number, because the mean of its divisors is an integer number (476861035560).

Almost surely, 2^{20071812217779} is an apocalyptic number.

20071812217779 is a deficient number, since it is larger than the sum of its proper divisors (14262182342541).

20071812217779 is a wasteful number, since it uses less digits than its factorization.

20071812217779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815629 (or 815619 counting only the distinct ones).

The product of its (nonzero) digits is 1382976, while the sum is 54.

The spelling of 20071812217779 in words is "twenty trillion, seventy-one billion, eight hundred twelve million, two hundred seventeen thousand, seven hundred seventy-nine".