643552445 has 4 divisors (see below), whose sum is σ = 772262940. Its totient is φ = 514841952.

The previous prime is 643552421. The next prime is 643552453. The reversal of 643552445 is 544255346.

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

It can be written as a sum of positive squares in 2 ways, for example, as 380172004 + 263380441 = 19498^2 + 16229^2 .

It is a cyclic number.

It is not a de Polignac number, because 643552445 - 2¹⁰ = 643551421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643552399 and 643552408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64355240 + ... + 64355249.

It is an arithmetic number, because the mean of its divisors is an integer number (193065735).

Almost surely, 2^643552445 is an apocalyptic number.

It is an amenable number.

643552445 is a deficient number, since it is larger than the sum of its proper divisors (128710495).

643552445 is a wasteful number, since it uses less digits than its factorization.

643552445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128710494.

The product of its digits is 288000, while the sum is 38.

The square root of 643552445 is about 25368.3354794910. The cubic root of 643552445 is about 863.3654163212.

The spelling of 643552445 in words is "six hundred forty-three million, five hundred fifty-two thousand, four hundred forty-five".