638591269 has 2 divisors, whose sum is σ = 638591270. Its totient is φ = 638591268.

The previous prime is 638591257. The next prime is 638591341. The reversal of 638591269 is 962195836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 638219169 + 372100 = 25263^2 + 610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638591269 is a prime.

It is a super-2 number, since 2×638591269² = 815597617686060722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638591069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319295634 + 319295635.

It is an arithmetic number, because the mean of its divisors is an integer number (319295635).

Almost surely, 2^638591269 is an apocalyptic number.

It is an amenable number.

638591269 is a deficient number, since it is larger than the sum of its proper divisors (1).

638591269 is an equidigital number, since it uses as much as digits as its factorization.

638591269 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 49.

The square root of 638591269 is about 25270.3634520756. The cubic root of 638591269 is about 861.1411159089.

The spelling of 638591269 in words is "six hundred thirty-eight million, five hundred ninety-one thousand, two hundred sixty-nine".