6638731291 has 2 divisors, whose sum is σ = 6638731292. Its totient is φ = 6638731290.

The previous prime is 6638731289. The next prime is 6638731331. The reversal of 6638731291 is 1921378366.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6638731291 - 2¹ = 6638731289 is a prime.

It is a super-3 number, since 3×6638731291³ (a number of 30 digits) contains 333 as substring.

Together with 6638731289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (6638731691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319365645 + 3319365646.

It is an arithmetic number, because the mean of its divisors is an integer number (3319365646).

Almost surely, 2^6638731291 is an apocalyptic number.

6638731291 is a deficient number, since it is larger than the sum of its proper divisors (1).

6638731291 is an equidigital number, since it uses as much as digits as its factorization.

6638731291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 326592, while the sum is 46.

The square root of 6638731291 is about 81478.4099685309. The cubic root of 6638731291 is about 1879.4395578389.

The spelling of 6638731291 in words is "six billion, six hundred thirty-eight million, seven hundred thirty-one thousand, two hundred ninety-one".