20178217393 has 2 divisors, whose sum is σ = 20178217394. Its totient is φ = 20178217392.

The previous prime is 20178217349. The next prime is 20178217403. The reversal of 20178217393 is 39371287102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10328250384 + 9849967009 = 101628^2 + 99247^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20178217393 is a prime.

It is not a weakly prime, because it can be changed into another prime (20178217333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10089108696 + 10089108697.

It is an arithmetic number, because the mean of its divisors is an integer number (10089108697).

Almost surely, 2^20178217393 is an apocalyptic number.

It is an amenable number.

20178217393 is a deficient number, since it is larger than the sum of its proper divisors (1).

20178217393 is an equidigital number, since it uses as much as digits as its factorization.

20178217393 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 43.

The spelling of 20178217393 in words is "twenty billion, one hundred seventy-eight million, two hundred seventeen thousand, three hundred ninety-three".