645608441 has 4 divisors (see below), whose sum is σ = 645886800. Its totient is φ = 645330084.

The previous prime is 645608419. The next prime is 645608443. The reversal of 645608441 is 144806546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645608441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645608395 and 645608404.

It is not an unprimeable number, because it can be changed into a prime (645608443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135671 + ... + 140348.

It is an arithmetic number, because the mean of its divisors is an integer number (161471700).

Almost surely, 2^645608441 is an apocalyptic number.

It is an amenable number.

645608441 is a deficient number, since it is larger than the sum of its proper divisors (278359).

645608441 is a wasteful number, since it uses less digits than its factorization.

645608441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278358.

The product of its (nonzero) digits is 92160, while the sum is 38.

The square root of 645608441 is about 25408.8260452938. The cubic root of 645608441 is about 864.2838542253.

The spelling of 645608441 in words is "six hundred forty-five million, six hundred eight thousand, four hundred forty-one".