645439241 has 4 divisors (see below), whose sum is σ = 645495300. Its totient is φ = 645383184.

The previous prime is 645439237. The next prime is 645439339. The reversal of 645439241 is 142934546.

645439241 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 brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 142934546 = 2 ⋅71467273.

It can be written as a sum of positive squares in 2 ways, for example, as 337787641 + 307651600 = 18379^2 + 17540^2 .

It is a cyclic number.

It is not a de Polignac number, because 645439241 - 2² = 645439237 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645439195 and 645439204.

It is not an unprimeable number, because it can be changed into a prime (645439741) 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, 3746 + ... + 36123.

It is an arithmetic number, because the mean of its divisors is an integer number (161373825).

Almost surely, 2^645439241 is an apocalyptic number.

It is an amenable number.

645439241 is a deficient number, since it is larger than the sum of its proper divisors (56059).

645439241 is a wasteful number, since it uses less digits than its factorization.

645439241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56058.

The product of its digits is 103680, while the sum is 38.

The square root of 645439241 is about 25405.4962754125. The cubic root of 645439241 is about 864.2083442640.

The spelling of 645439241 in words is "six hundred forty-five million, four hundred thirty-nine thousand, two hundred forty-one".