643741741 has 4 divisors (see below), whose sum is σ = 645347484. Its totient is φ = 642136000.

The previous prime is 643741711. The next prime is 643741757. The reversal of 643741741 is 147147346.

It is a happy number.

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 408242025 + 235499716 = 20205^2 + 15346^2 .

It is a cyclic number.

It is not a de Polignac number, because 643741741 - 2⁷ = 643741613 is a prime.

It is a super-2 number, since 2×643741741² = 828806858211422162, which contains 22 as substring.

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 643741741.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643741711) 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, 802270 + ... + 803071.

It is an arithmetic number, because the mean of its divisors is an integer number (161336871).

Almost surely, 2^643741741 is an apocalyptic number.

It is an amenable number.

643741741 is a deficient number, since it is larger than the sum of its proper divisors (1605743).

643741741 is a wasteful number, since it uses less digits than its factorization.

643741741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1605742.

The product of its digits is 56448, while the sum is 37.

The square root of 643741741 is about 25372.0661555184. The cubic root of 643741741 is about 863.4500587875.

The spelling of 643741741 in words is "six hundred forty-three million, seven hundred forty-one thousand, seven hundred forty-one".