640321039 has 2 divisors, whose sum is σ = 640321040. Its totient is φ = 640321038.

The previous prime is 640321009. The next prime is 640321069. The reversal of 640321039 is 930123046.

It is a balanced prime because it is at equal distance from previous prime (640321009) and next prime (640321069).

It is a cyclic number.

It is not a de Polignac number, because 640321039 - 2¹⁷ = 640189967 is a prime.

It is a super-2 number, since 2×640321039² = 820022065972079042, which contains 22 as substring.

It is equal to p_33316417 and since 640321039 and 33316417 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 640320998 and 640321016.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640321009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320160519 + 320160520.

It is an arithmetic number, because the mean of its divisors is an integer number (320160520).

Almost surely, 2^640321039 is an apocalyptic number.

640321039 is a deficient number, since it is larger than the sum of its proper divisors (1).

640321039 is an equidigital number, since it uses as much as digits as its factorization.

640321039 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 640321039 is about 25304.5655761959. The cubic root of 640321039 is about 861.9179472503.

The spelling of 640321039 in words is "six hundred forty million, three hundred twenty-one thousand, thirty-nine".