643342477 has 2 divisors, whose sum is σ = 643342478. Its totient is φ = 643342476.

The previous prime is 643342471. The next prime is 643342487. The reversal of 643342477 is 774243346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 622053481 + 21288996 = 24941^2 + 4614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643342477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643342471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321671238 + 321671239.

It is an arithmetic number, because the mean of its divisors is an integer number (321671239).

Almost surely, 2^643342477 is an apocalyptic number.

It is an amenable number.

643342477 is a deficient number, since it is larger than the sum of its proper divisors (1).

643342477 is an equidigital number, since it uses as much as digits as its factorization.

643342477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 338688, while the sum is 40.

The square root of 643342477 is about 25364.1967544805. The cubic root of 643342477 is about 863.2715110875.

The spelling of 643342477 in words is "six hundred forty-three million, three hundred forty-two thousand, four hundred seventy-seven".