643278445 has 16 divisors (see below), whose sum is σ = 781200000. Its totient is φ = 508483008.

The previous prime is 643278439. The next prime is 643278451. The reversal of 643278445 is 544872346.

It is an interprime number because it is at equal distance from previous prime (643278439) and next prime (643278451).

It is a cyclic number.

It is not a de Polignac number, because 643278445 - 2⁵ = 643278413 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 146086 + ... + 150424.

It is an arithmetic number, because the mean of its divisors is an integer number (48825000).

Almost surely, 2^643278445 is an apocalyptic number.

It is an amenable number.

643278445 is a deficient number, since it is larger than the sum of its proper divisors (137921555).

643278445 is a wasteful number, since it uses less digits than its factorization.

643278445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4692.

The product of its digits is 645120, while the sum is 43.

The square root of 643278445 is about 25362.9344713895. The cubic root of 643278445 is about 863.2428696109.

The spelling of 643278445 in words is "six hundred forty-three million, two hundred seventy-eight thousand, four hundred forty-five".