643534853 has 8 divisors (see below), whose sum is σ = 716935800. Its totient is φ = 573547968.

The previous prime is 643534849. The next prime is 643534877. The reversal of 643534853 is 358435346.

It can be written as a sum of positive squares in 4 ways, for example, as 9351364 + 634183489 = 3058^2 + 25183^2 .

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 643534853 - 2² = 643534849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 643534853.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643534253) 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, 853118 + ... + 853871.

It is an arithmetic number, because the mean of its divisors is an integer number (89616975).

Almost surely, 2^643534853 is an apocalyptic number.

It is an amenable number.

643534853 is a deficient number, since it is larger than the sum of its proper divisors (73400947).

643534853 is a wasteful number, since it uses less digits than its factorization.

643534853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707031.

The product of its digits is 518400, while the sum is 41.

The square root of 643534853 is about 25367.9887456613. The cubic root of 643534853 is about 863.3575493308.

The spelling of 643534853 in words is "six hundred forty-three million, five hundred thirty-four thousand, eight hundred fifty-three".