638198833 has 2 divisors, whose sum is σ = 638198834. Its totient is φ = 638198832.

The previous prime is 638198831. The next prime is 638198837. The reversal of 638198833 is 338891836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 612463504 + 25735329 = 24748^2 + 5073^2 .

It is a cyclic number.

It is not a de Polignac number, because 638198833 - 2¹ = 638198831 is a prime.

Together with 638198831, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (638198831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319099416 + 319099417.

It is an arithmetic number, because the mean of its divisors is an integer number (319099417).

Almost surely, 2^638198833 is an apocalyptic number.

It is an amenable number.

638198833 is a deficient number, since it is larger than the sum of its proper divisors (1).

638198833 is an equidigital number, since it uses as much as digits as its factorization.

638198833 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 49.

The square root of 638198833 is about 25262.5975109449. The cubic root of 638198833 is about 860.9646796182.

The spelling of 638198833 in words is "six hundred thirty-eight million, one hundred ninety-eight thousand, eight hundred thirty-three".