643898041 has 4 divisors (see below), whose sum is σ = 671893632. Its totient is φ = 615902452.

The previous prime is 643898027. The next prime is 643898051. The reversal of 643898041 is 140898346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643898041 - 2¹³ = 643889849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643898051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13997761 + ... + 13997806.

It is an arithmetic number, because the mean of its divisors is an integer number (167973408).

Almost surely, 2^643898041 is an apocalyptic number.

It is an amenable number.

643898041 is a deficient number, since it is larger than the sum of its proper divisors (27995591).

643898041 is a wasteful number, since it uses less digits than its factorization.

643898041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27995590.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 643898041 is about 25375.1461276581. The cubic root of 643898041 is about 863.5199348028.

The spelling of 643898041 in words is "six hundred forty-three million, eight hundred ninety-eight thousand, forty-one".