643507477 has 8 divisors (see below), whose sum is σ = 704856600. Its totient is φ = 584769024.

The previous prime is 643507457. The next prime is 643507481. The reversal of 643507477 is 774705346.

It can be written as a sum of positive squares in 4 ways, for example, as 288524196 + 354983281 = 16986^2 + 18841^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643507477 - 2²⁷ = 509289749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643507457) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 652152 + ... + 653137.

It is an arithmetic number, because the mean of its divisors is an integer number (88107075).

Almost surely, 2^643507477 is an apocalyptic number.

It is an amenable number.

643507477 is a deficient number, since it is larger than the sum of its proper divisors (61349123).

643507477 is a wasteful number, since it uses less digits than its factorization.

643507477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1305335.

The product of its (nonzero) digits is 493920, while the sum is 43.

The square root of 643507477 is about 25367.4491622630. The cubic root of 643507477 is about 863.3453067349.

The spelling of 643507477 in words is "six hundred forty-three million, five hundred seven thousand, four hundred seventy-seven".