639123269 has 2 divisors, whose sum is σ = 639123270. Its totient is φ = 639123268.

The previous prime is 639123263. The next prime is 639123271. The reversal of 639123269 is 962321936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 607031044 + 32092225 = 24638^2 + 5665^2 .

It is a cyclic number.

It is not a de Polignac number, because 639123269 - 2⁸ = 639123013 is a prime.

It is a super-2 number, since 2×639123269² = 816957105954492722, which contains 22 as substring.

Together with 639123271, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639123263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319561634 + 319561635.

It is an arithmetic number, because the mean of its divisors is an integer number (319561635).

Almost surely, 2^639123269 is an apocalyptic number.

It is an amenable number.

639123269 is a deficient number, since it is larger than the sum of its proper divisors (1).

639123269 is an equidigital number, since it uses as much as digits as its factorization.

639123269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 104976, while the sum is 41.

The square root of 639123269 is about 25280.8874250885. The cubic root of 639123269 is about 861.3801837526.

The spelling of 639123269 in words is "six hundred thirty-nine million, one hundred twenty-three thousand, two hundred sixty-nine".