20556078861 has 8 divisors (see below), whose sum is σ = 27409228704. Its totient is φ = 13703490800.

The previous prime is 20556078847. The next prime is 20556078901. The reversal of 20556078861 is 16887065502.

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

It is a cyclic number.

It is not a de Polignac number, because 20556078861 - 2³⁰ = 19482337037 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20556078861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20556078821) 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 7 ways as a sum of consecutive naturals, for example, 45990 + ... + 207911.

It is an arithmetic number, because the mean of its divisors is an integer number (3426153588).

Almost surely, 2^20556078861 is an apocalyptic number.

It is an amenable number.

20556078861 is a deficient number, since it is larger than the sum of its proper divisors (6853149843).

20556078861 is a wasteful number, since it uses less digits than its factorization.

20556078861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280891.

The product of its (nonzero) digits is 806400, while the sum is 48.

The spelling of 20556078861 in words is "twenty billion, five hundred fifty-six million, seventy-eight thousand, eight hundred sixty-one".