643574249 has 4 divisors (see below), whose sum is σ = 658541136. Its totient is φ = 628607364.

The previous prime is 643574233. The next prime is 643574257. The reversal of 643574249 is 942475346.

643574249 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 942475346 = 2 ⋅471237673.

It is a cyclic number.

It is not a de Polignac number, because 643574249 - 2⁴ = 643574233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643574549) 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, 7483379 + ... + 7483464.

It is an arithmetic number, because the mean of its divisors is an integer number (164635284).

Almost surely, 2^643574249 is an apocalyptic number.

It is an amenable number.

643574249 is a deficient number, since it is larger than the sum of its proper divisors (14966887).

643574249 is a wasteful number, since it uses less digits than its factorization.

643574249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14966886.

The product of its digits is 725760, while the sum is 44.

The square root of 643574249 is about 25368.7652241886. The cubic root of 643574249 is about 863.3751666827.

The spelling of 643574249 in words is "six hundred forty-three million, five hundred seventy-four thousand, two hundred forty-nine".