638491479739 has 2 divisors, whose sum is σ = 638491479740. Its totient is φ = 638491479738.

The previous prime is 638491479643. The next prime is 638491479751. The reversal of 638491479739 is 937974194836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638491479739 - 2²⁵ = 638457925307 is a prime.

It is not a weakly prime, because it can be changed into another prime (638491479239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319245739869 + 319245739870.

It is an arithmetic number, because the mean of its divisors is an integer number (319245739870).

Almost surely, 2^638491479739 is an apocalyptic number.

638491479739 is a deficient number, since it is larger than the sum of its proper divisors (1).

638491479739 is an equidigital number, since it uses as much as digits as its factorization.

638491479739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 246903552, while the sum is 70.

The spelling of 638491479739 in words is "six hundred thirty-eight billion, four hundred ninety-one million, four hundred seventy-nine thousand, seven hundred thirty-nine".