639200173 has 2 divisors, whose sum is σ = 639200174. Its totient is φ = 639200172.

The previous prime is 639200137. The next prime is 639200201. The reversal of 639200173 is 371002936.

It is the 10322-nd star number.

Together with previous prime (639200137) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 442134729 + 197065444 = 21027^2 + 14038^2 .

It is a cyclic number.

It is not a de Polignac number, because 639200173 - 2⁹ = 639199661 is a prime.

It is a super-2 number, since 2×639200173² = 817153722326459858, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639200473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319600086 + 319600087.

It is an arithmetic number, because the mean of its divisors is an integer number (319600087).

Almost surely, 2^639200173 is an apocalyptic number.

It is an amenable number.

639200173 is a deficient number, since it is larger than the sum of its proper divisors (1).

639200173 is an equidigital number, since it uses as much as digits as its factorization.

639200173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 639200173 is about 25282.4083702483. The cubic root of 639200173 is about 861.4147315611.

The spelling of 639200173 in words is "six hundred thirty-nine million, two hundred thousand, one hundred seventy-three".