643466137 has 2 divisors, whose sum is σ = 643466138. Its totient is φ = 643466136.

The previous prime is 643466129. The next prime is 643466189. The reversal of 643466137 is 731664346.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 421932681 + 221533456 = 20541^2 + 14884^2 .

It is a cyclic number.

It is not a de Polignac number, because 643466137 - 2³ = 643466129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643466137.

It is not a weakly prime, because it can be changed into another prime (643466107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321733068 + 321733069.

It is an arithmetic number, because the mean of its divisors is an integer number (321733069).

Almost surely, 2^643466137 is an apocalyptic number.

It is an amenable number.

643466137 is a deficient number, since it is larger than the sum of its proper divisors (1).

643466137 is an equidigital number, since it uses as much as digits as its factorization.

643466137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 40.

The square root of 643466137 is about 25366.6343254284. The cubic root of 643466137 is about 863.3268187553.

The spelling of 643466137 in words is "six hundred forty-three million, four hundred sixty-six thousand, one hundred thirty-seven".