20578974517 has 2 divisors, whose sum is σ = 20578974518. Its totient is φ = 20578974516.

The previous prime is 20578974511. The next prime is 20578974539. The reversal of 20578974517 is 71547987502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20023948036 + 555026481 = 141506^2 + 23559^2 .

It is a cyclic number.

It is not a de Polignac number, because 20578974517 - 2³ = 20578974509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20578974511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10289487258 + 10289487259.

It is an arithmetic number, because the mean of its divisors is an integer number (10289487259).

Almost surely, 2^20578974517 is an apocalyptic number.

It is an amenable number.

20578974517 is a deficient number, since it is larger than the sum of its proper divisors (1).

20578974517 is an equidigital number, since it uses as much as digits as its factorization.

20578974517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4939200, while the sum is 55.

The spelling of 20578974517 in words is "twenty billion, five hundred seventy-eight million, nine hundred seventy-four thousand, five hundred seventeen".