638323919 has 2 divisors, whose sum is σ = 638323920. Its totient is φ = 638323918.

The previous prime is 638323913. The next prime is 638323937. The reversal of 638323919 is 919323836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638323919 - 2⁸ = 638323663 is a prime.

It is a super-2 number, since 2×638323919² = 814914851135037122, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638323919.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638323913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319161959 + 319161960.

It is an arithmetic number, because the mean of its divisors is an integer number (319161960).

Almost surely, 2^638323919 is an apocalyptic number.

638323919 is a deficient number, since it is larger than the sum of its proper divisors (1).

638323919 is an equidigital number, since it uses as much as digits as its factorization.

638323919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 44.

The square root of 638323919 is about 25265.0731049803. The cubic root of 638323919 is about 861.0209251993.

The spelling of 638323919 in words is "six hundred thirty-eight million, three hundred twenty-three thousand, nine hundred nineteen".