643143451 has 4 divisors (see below), whose sum is σ = 647460000. Its totient is φ = 638826904.

The previous prime is 643143443. The next prime is 643143461. The reversal of 643143451 is 154341346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643143451 - 2³ = 643143443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643143421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2158051 + ... + 2158348.

It is an arithmetic number, because the mean of its divisors is an integer number (161865000).

Almost surely, 2^643143451 is an apocalyptic number.

643143451 is a deficient number, since it is larger than the sum of its proper divisors (4316549).

643143451 is a wasteful number, since it uses less digits than its factorization.

643143451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4316548.

The product of its digits is 17280, while the sum is 31.

The square root of 643143451 is about 25360.2730860691. The cubic root of 643143451 is about 863.1824806449.

Adding to 643143451 its reverse (154341346), we get a palindrome (797484797).

The spelling of 643143451 in words is "six hundred forty-three million, one hundred forty-three thousand, four hundred fifty-one".