645136563 has 8 divisors (see below), whose sum is σ = 863530128. Its totient is φ = 428417024.

The previous prime is 645136561. The next prime is 645136573. The reversal of 645136563 is 365631546.

It is a happy number.

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 645136563 - 2¹ = 645136561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645136561) 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, 417606 + ... + 419147.

It is an arithmetic number, because the mean of its divisors is an integer number (107941266).

Almost surely, 2^645136563 is an apocalyptic number.

645136563 is a deficient number, since it is larger than the sum of its proper divisors (218393565).

645136563 is a wasteful number, since it uses less digits than its factorization.

645136563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837013.

The product of its digits is 194400, while the sum is 39.

The square root of 645136563 is about 25399.5386375422. The cubic root of 645136563 is about 864.0732333008.

The spelling of 645136563 in words is "six hundred forty-five million, one hundred thirty-six thousand, five hundred sixty-three".