1643205241 has 4 divisors (see below), whose sum is σ = 1648455412. Its totient is φ = 1637955072.

The previous prime is 1643205233. The next prime is 1643205271. The reversal of 1643205241 is 1425023461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1425023461 = 10141 ⋅140521.

It can be written as a sum of positive squares in 2 ways, for example, as 669515625 + 973689616 = 25875^2 + 31204^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643205241 - 2³ = 1643205233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1643205271) 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, 2624616 + ... + 2625241.

It is an arithmetic number, because the mean of its divisors is an integer number (412113853).

Almost surely, 2^1643205241 is an apocalyptic number.

It is an amenable number.

1643205241 is a deficient number, since it is larger than the sum of its proper divisors (5250171).

1643205241 is an equidigital number, since it uses as much as digits as its factorization.

1643205241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5250170.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 1643205241 is about 40536.4680380519. The cubic root of 1643205241 is about 1180.0414715387.

The spelling of 1643205241 in words is "one billion, six hundred forty-three million, two hundred five thousand, two hundred forty-one".