639524161 has 2 divisors, whose sum is σ = 639524162. Its totient is φ = 639524160.

The previous prime is 639524117. The next prime is 639524209. The reversal of 639524161 is 161425936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 347114161 + 292410000 = 18631^2 + 17100^2 .

It is a cyclic number.

It is not a de Polignac number, because 639524161 - 2⁷ = 639524033 is a prime.

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 639524161.

It is not a weakly prime, because it can be changed into another prime (639524101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319762080 + 319762081.

It is an arithmetic number, because the mean of its divisors is an integer number (319762081).

Almost surely, 2^639524161 is an apocalyptic number.

It is an amenable number.

639524161 is a deficient number, since it is larger than the sum of its proper divisors (1).

639524161 is an equidigital number, since it uses as much as digits as its factorization.

639524161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 37.

The square root of 639524161 is about 25288.8149386245. The cubic root of 639524161 is about 861.5602472163.

It can be divided in two parts, 639 and 524161, that added together give a triangular number (524800 = T₁₀₂₄).

The spelling of 639524161 in words is "six hundred thirty-nine million, five hundred twenty-four thousand, one hundred sixty-one".