643426376 has 8 divisors (see below), whose sum is σ = 1206424470. Its totient is φ = 321713184.

The previous prime is 643426339. The next prime is 643426409. The reversal of 643426376 is 673624346.

It can be written as a sum of positive squares in only one way, i.e., 485320900 + 158105476 = 22030^2 + 12574^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40214141 + ... + 40214156.

Almost surely, 2^643426376 is an apocalyptic number.

It is an amenable number.

643426376 is a deficient number, since it is larger than the sum of its proper divisors (562998094).

643426376 is a wasteful number, since it uses less digits than its factorization.

643426376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80428303 (or 80428299 counting only the distinct ones).

The product of its digits is 435456, while the sum is 41.

The square root of 643426376 is about 25365.8505869604. The cubic root of 643426376 is about 863.3090361854.

The spelling of 643426376 in words is "six hundred forty-three million, four hundred twenty-six thousand, three hundred seventy-six".