18939928457 has 2 divisors, whose sum is σ = 18939928458. Its totient is φ = 18939928456.

The previous prime is 18939928373. The next prime is 18939928471. The reversal of 18939928457 is 75482993981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9565622416 + 9374306041 = 97804^2 + 96821^2 .

It is a cyclic number.

It is not a de Polignac number, because 18939928457 - 2¹² = 18939924361 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18939928393 and 18939928402.

It is not a weakly prime, because it can be changed into another prime (18939928477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9469964228 + 9469964229.

It is an arithmetic number, because the mean of its divisors is an integer number (9469964229).

Almost surely, 2^18939928457 is an apocalyptic number.

It is an amenable number.

18939928457 is a deficient number, since it is larger than the sum of its proper divisors (1).

18939928457 is an equidigital number, since it uses as much as digits as its factorization.

18939928457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39191040, while the sum is 65.

The spelling of 18939928457 in words is "eighteen billion, nine hundred thirty-nine million, nine hundred twenty-eight thousand, four hundred fifty-seven".