638529973 has 2 divisors, whose sum is σ = 638529974. Its totient is φ = 638529972.

The previous prime is 638529967. The next prime is 638529977. The reversal of 638529973 is 379925836.

638529973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635947524 + 2582449 = 25218^2 + 1607^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638529973 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638529973.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638529977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319264986 + 319264987.

It is an arithmetic number, because the mean of its divisors is an integer number (319264987).

Almost surely, 2^638529973 is an apocalyptic number.

It is an amenable number.

638529973 is a deficient number, since it is larger than the sum of its proper divisors (1).

638529973 is an equidigital number, since it uses as much as digits as its factorization.

638529973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2449440, while the sum is 52.

The square root of 638529973 is about 25269.1506188871. The cubic root of 638529973 is about 861.1135624500.

The spelling of 638529973 in words is "six hundred thirty-eight million, five hundred twenty-nine thousand, nine hundred seventy-three".