643456477 has 6 divisors (see below), whose sum is σ = 683533658. Its totient is φ = 605605824.

The previous prime is 643456439. The next prime is 643456481. The reversal of 643456477 is 774654346.

It can be written as a sum of positive squares in 3 ways, for example, as 144336196 + 499120281 = 12014^2 + 22341^2 .

It is a de Polignac number, because none of the positive numbers 2^k-643456477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643456577) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1112958 + ... + 1113535.

Almost surely, 2^643456477 is an apocalyptic number.

It is an amenable number.

643456477 is a deficient number, since it is larger than the sum of its proper divisors (40077181).

643456477 is a wasteful number, since it uses less digits than its factorization.

643456477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226527 (or 2226510 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 46.

The square root of 643456477 is about 25366.4439171122. The cubic root of 643456477 is about 863.3224985182.

The spelling of 643456477 in words is "six hundred forty-three million, four hundred fifty-six thousand, four hundred seventy-seven".