645739229 has 8 divisors (see below), whose sum is σ = 659156472. Its totient is φ = 632413440.

The previous prime is 645739219. The next prime is 645739231. The reversal of 645739229 is 922937546.

It can be written as a sum of positive squares in 4 ways, for example, as 51696100 + 594043129 = 7190^2 + 24373^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645739229 - 2²⁴ = 628962013 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645739219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8504 + ... + 36929.

It is an arithmetic number, because the mean of its divisors is an integer number (82394559).

Almost surely, 2^645739229 is an apocalyptic number.

It is an amenable number.

645739229 is a deficient number, since it is larger than the sum of its proper divisors (13417243).

645739229 is a wasteful number, since it uses less digits than its factorization.

645739229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45727.

The product of its digits is 816480, while the sum is 47.

The square root of 645739229 is about 25411.3995875867. The cubic root of 645739229 is about 864.3422127789.

The spelling of 645739229 in words is "six hundred forty-five million, seven hundred thirty-nine thousand, two hundred twenty-nine".