643612439 has 2 divisors, whose sum is σ = 643612440. Its totient is φ = 643612438.

The previous prime is 643612397. The next prime is 643612493. The reversal of 643612439 is 934216346.

It is a happy number.

Together with next prime (643612493) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643612439 - 2²⁰ = 642563863 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_33478580 and since 643612439 and 33478580 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643612339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321806219 + 321806220.

It is an arithmetic number, because the mean of its divisors is an integer number (321806220).

Almost surely, 2^643612439 is an apocalyptic number.

643612439 is a deficient number, since it is larger than the sum of its proper divisors (1).

643612439 is an equidigital number, since it uses as much as digits as its factorization.

643612439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 38.

The square root of 643612439 is about 25369.5179102797. The cubic root of 643612439 is about 863.3922440417.

The spelling of 643612439 in words is "six hundred forty-three million, six hundred twelve thousand, four hundred thirty-nine".