639091 has 2 divisors, whose sum is σ = 639092. Its totient is φ = 639090.

The previous prime is 639083. The next prime is 639137. The reversal of 639091 is 190936.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639091 - 2³ = 639083 is a prime.

It is not a weakly prime, because it can be changed into another prime (639011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319545 + 319546.

It is an arithmetic number, because the mean of its divisors is an integer number (319546).

2⁶³⁹⁰⁹¹ is an apocalyptic number.

639091 is a deficient number, since it is larger than the sum of its proper divisors (1).

639091 is an equidigital number, since it uses as much as digits as its factorization.

639091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 639091 is about 799.4316731279. The cubic root of 639091 is about 86.1365686630.

The spelling of 639091 in words is "six hundred thirty-nine thousand, ninety-one".