643477451 has 4 divisors (see below), whose sum is σ = 646744032. Its totient is φ = 640210872.

The previous prime is 643477391. The next prime is 643477453. The reversal of 643477451 is 154774346.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643477451 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643477399 and 643477408.

It is not an unprimeable number, because it can be changed into a prime (643477453) 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, 1632995 + ... + 1633388.

It is an arithmetic number, because the mean of its divisors is an integer number (161686008).

Almost surely, 2^643477451 is an apocalyptic number.

643477451 is a deficient number, since it is larger than the sum of its proper divisors (3266581).

643477451 is a wasteful number, since it uses less digits than its factorization.

643477451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3266580.

The product of its digits is 282240, while the sum is 41.

The square root of 643477451 is about 25366.8573339308. The cubic root of 643477451 is about 863.3318786550.

The spelling of 643477451 in words is "six hundred forty-three million, four hundred seventy-seven thousand, four hundred fifty-one".