643451047 has 2 divisors, whose sum is σ = 643451048. Its totient is φ = 643451046.

The previous prime is 643451033. The next prime is 643451063. The reversal of 643451047 is 740154346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643451047 - 2¹⁹ = 642926759 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643421047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321725523 + 321725524.

It is an arithmetic number, because the mean of its divisors is an integer number (321725524).

Almost surely, 2^643451047 is an apocalyptic number.

643451047 is a deficient number, since it is larger than the sum of its proper divisors (1).

643451047 is an equidigital number, since it uses as much as digits as its factorization.

643451047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 34.

The square root of 643451047 is about 25366.3368857232. The cubic root of 643451047 is about 863.3200700430.

The spelling of 643451047 in words is "six hundred forty-three million, four hundred fifty-one thousand, forty-seven".