643958418427 has 2 divisors, whose sum is σ = 643958418428. Its totient is φ = 643958418426.

The previous prime is 643958418421. The next prime is 643958418431. The reversal of 643958418427 is 724814859346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643958418427 - 2³ = 643958418419 is a prime.

It is not a weakly prime, because it can be changed into another prime (643958418421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321979209213 + 321979209214.

It is an arithmetic number, because the mean of its divisors is an integer number (321979209214).

Almost surely, 2^643958418427 is an apocalyptic number.

643958418427 is a deficient number, since it is larger than the sum of its proper divisors (1).

643958418427 is an equidigital number, since it uses as much as digits as its factorization.

643958418427 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46448640, while the sum is 61.

The spelling of 643958418427 in words is "six hundred forty-three billion, nine hundred fifty-eight million, four hundred eighteen thousand, four hundred twenty-seven".