640069123 has 2 divisors, whose sum is σ = 640069124. Its totient is φ = 640069122.

The previous prime is 640069109. The next prime is 640069127. The reversal of 640069123 is 321960046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640069123 - 2²⁵ = 606514691 is a prime.

It is not a weakly prime, because it can be changed into another prime (640069127) 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, 320034561 + 320034562.

It is an arithmetic number, because the mean of its divisors is an integer number (320034562).

Almost surely, 2^640069123 is an apocalyptic number.

640069123 is a deficient number, since it is larger than the sum of its proper divisors (1).

640069123 is an equidigital number, since it uses as much as digits as its factorization.

640069123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 640069123 is about 25299.5874077029. The cubic root of 640069123 is about 861.8049001019.

The spelling of 640069123 in words is "six hundred forty million, sixty-nine thousand, one hundred twenty-three".