643505476 has 24 divisors (see below), whose sum is σ = 1167304320. Its totient is φ = 310034592.

The previous prime is 643505461. The next prime is 643505543. The reversal of 643505476 is 674505346.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55365 + ... + 65971.

It is an arithmetic number, because the mean of its divisors is an integer number (48637680).

Almost surely, 2^643505476 is an apocalyptic number.

It is an amenable number.

643505476 is a deficient number, since it is larger than the sum of its proper divisors (523798844).

643505476 is a wasteful number, since it uses less digits than its factorization.

643505476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11163 (or 11161 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 40.

The square root of 643505476 is about 25367.4097219247. The cubic root of 643505476 is about 863.3444118705.

The spelling of 643505476 in words is "six hundred forty-three million, five hundred five thousand, four hundred seventy-six".