644164545 has 8 divisors (see below), whose sum is σ = 1030663296. Its totient is φ = 343554416.

The previous prime is 644164541. The next prime is 644164579. The reversal of 644164545 is 545461446.

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 644164545 - 2² = 644164541 is a prime.

It is a super-2 number, since 2×644164545² = 829895922070114050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644164541) 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, 21472137 + ... + 21472166.

It is an arithmetic number, because the mean of its divisors is an integer number (128832912).

Almost surely, 2^644164545 is an apocalyptic number.

It is an amenable number.

644164545 is a deficient number, since it is larger than the sum of its proper divisors (386498751).

644164545 is a wasteful number, since it uses less digits than its factorization.

644164545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42944311.

The product of its digits is 230400, while the sum is 39.

The square root of 644164545 is about 25380.3968645094. The cubic root of 644164545 is about 863.6390529237.

The spelling of 644164545 in words is "six hundred forty-four million, one hundred sixty-four thousand, five hundred forty-five".