643316951 has 2 divisors, whose sum is σ = 643316952. Its totient is φ = 643316950.

The previous prime is 643316917. The next prime is 643316957. The reversal of 643316951 is 159613346.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643316951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643316957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321658475 + 321658476.

It is an arithmetic number, because the mean of its divisors is an integer number (321658476).

Almost surely, 2^643316951 is an apocalyptic number.

643316951 is a deficient number, since it is larger than the sum of its proper divisors (1).

643316951 is an equidigital number, since it uses as much as digits as its factorization.

643316951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 38.

The square root of 643316951 is about 25363.6935598899. The cubic root of 643316951 is about 863.2600935503.

The spelling of 643316951 in words is "six hundred forty-three million, three hundred sixteen thousand, nine hundred fifty-one".