643612397 has 2 divisors, whose sum is σ = 643612398. Its totient is φ = 643612396.

The previous prime is 643612393. The next prime is 643612439. The reversal of 643612397 is 793216346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 533656201 + 109956196 = 23101^2 + 10486^2 .

It is a cyclic number.

It is not a de Polignac number, because 643612397 - 2² = 643612393 is a prime.

It is a super-3 number, since 3×643612397³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643612393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321806198 + 321806199.

It is an arithmetic number, because the mean of its divisors is an integer number (321806199).

Almost surely, 2^643612397 is an apocalyptic number.

It is an amenable number.

643612397 is a deficient number, since it is larger than the sum of its proper divisors (1).

643612397 is an equidigital number, since it uses as much as digits as its factorization.

643612397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 41.

The square root of 643612397 is about 25369.5170825146. The cubic root of 643612397 is about 863.3922252610.

The spelling of 643612397 in words is "six hundred forty-three million, six hundred twelve thousand, three hundred ninety-seven".