643378427 has 8 divisors (see below), whose sum is σ = 681043440. Its totient is φ = 606745440.

The previous prime is 643378403. The next prime is 643378429. The reversal of 643378427 is 724873346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643378427 - 2⁶ = 643378363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643378429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 256724 + ... + 259217.

It is an arithmetic number, because the mean of its divisors is an integer number (85130430).

Almost surely, 2^643378427 is an apocalyptic number.

643378427 is a deficient number, since it is larger than the sum of its proper divisors (37665013).

643378427 is a wasteful number, since it uses less digits than its factorization.

643378427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516013.

The product of its digits is 677376, while the sum is 44.

The square root of 643378427 is about 25364.9054206792. The cubic root of 643378427 is about 863.2875906687.

The spelling of 643378427 in words is "six hundred forty-three million, three hundred seventy-eight thousand, four hundred twenty-seven".