643019215977449 has 2 divisors, whose sum is σ = 643019215977450. Its totient is φ = 643019215977448.

The previous prime is 643019215977433. The next prime is 643019215977521. The reversal of 643019215977449 is 944779512910346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 389800579983424 + 253218635994025 = 19743368^2 + 15912845^2 .

It is a cyclic number.

It is not a de Polignac number, because 643019215977449 - 2⁴ = 643019215977433 is a prime.

It is not a weakly prime, because it can be changed into another prime (643019215977349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321509607988724 + 321509607988725.

It is an arithmetic number, because the mean of its divisors is an integer number (321509607988725).

Almost surely, 2^{643019215977449} is an apocalyptic number.

It is an amenable number.

643019215977449 is a deficient number, since it is larger than the sum of its proper divisors (1).

643019215977449 is an equidigital number, since it uses as much as digits as its factorization.

643019215977449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 411505920, while the sum is 71.

The spelling of 643019215977449 in words is "six hundred forty-three trillion, nineteen billion, two hundred fifteen million, nine hundred seventy-seven thousand, four hundred forty-nine".