20556174647 has 2 divisors, whose sum is σ = 20556174648. Its totient is φ = 20556174646.

The previous prime is 20556174637. The next prime is 20556174649. The reversal of 20556174647 is 74647165502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20556174647 - 2¹⁴ = 20556158263 is a prime.

It is a super-2 number, since 2×20556174647² (a number of 21 digits) contains 22 as substring.

Together with 20556174649, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20556174649) 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 as a sum of consecutive naturals, namely, 10278087323 + 10278087324.

It is an arithmetic number, because the mean of its divisors is an integer number (10278087324).

Almost surely, 2^20556174647 is an apocalyptic number.

20556174647 is a deficient number, since it is larger than the sum of its proper divisors (1).

20556174647 is an equidigital number, since it uses as much as digits as its factorization.

20556174647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1411200, while the sum is 47.

The spelling of 20556174647 in words is "twenty billion, five hundred fifty-six million, one hundred seventy-four thousand, six hundred forty-seven".