643747451 has 2 divisors, whose sum is σ = 643747452. Its totient is φ = 643747450.

The previous prime is 643747439. The next prime is 643747463. The reversal of 643747451 is 154747346.

It is a balanced prime because it is at equal distance from previous prime (643747439) and next prime (643747463).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643747451 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643747399 and 643747408.

It is not a weakly prime, because it can be changed into another prime (643747411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321873725 + 321873726.

It is an arithmetic number, because the mean of its divisors is an integer number (321873726).

Almost surely, 2^643747451 is an apocalyptic number.

643747451 is a deficient number, since it is larger than the sum of its proper divisors (1).

643747451 is an equidigital number, since it uses as much as digits as its factorization.

643747451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282240, while the sum is 41.

The square root of 643747451 is about 25372.1786805942. The cubic root of 643747451 is about 863.4526117188.

The spelling of 643747451 in words is "six hundred forty-three million, seven hundred forty-seven thousand, four hundred fifty-one".