645538361 has 8 divisors (see below), whose sum is σ = 695439360. Its totient is φ = 595672272.

The previous prime is 645538349. The next prime is 645538381. The reversal of 645538361 is 163835546.

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

It is not a de Polignac number, because 645538361 - 2¹⁰ = 645537337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645538301) 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, 39650 + ... + 53508.

It is an arithmetic number, because the mean of its divisors is an integer number (86929920).

Almost surely, 2^645538361 is an apocalyptic number.

It is an amenable number.

645538361 is a deficient number, since it is larger than the sum of its proper divisors (49900999).

645538361 is a wasteful number, since it uses less digits than its factorization.

645538361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17455.

The product of its digits is 259200, while the sum is 41.

The square root of 645538361 is about 25407.4469595038. The cubic root of 645538361 is about 864.2525807783.

The spelling of 645538361 in words is "six hundred forty-five million, five hundred thirty-eight thousand, three hundred sixty-one".