644864601 has 16 divisors (see below), whose sum is σ = 891176000. Its totient is φ = 414445248.

The previous prime is 644864567. The next prime is 644864603. The reversal of 644864601 is 106468446.

It is not a de Polignac number, because 644864601 - 2⁶ = 644864537 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644864601.

It is not an unprimeable number, because it can be changed into a prime (644864603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14551 + ... + 38748.

It is an arithmetic number, because the mean of its divisors is an integer number (55698500).

Almost surely, 2^644864601 is an apocalyptic number.

It is an amenable number.

644864601 is a deficient number, since it is larger than the sum of its proper divisors (246311399).

644864601 is a wasteful number, since it uses less digits than its factorization.

644864601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53448.

The product of its (nonzero) digits is 110592, while the sum is 39.

The square root of 644864601 is about 25394.1843932819. The cubic root of 644864601 is about 863.9517974544.

The spelling of 644864601 in words is "six hundred forty-four million, eight hundred sixty-four thousand, six hundred one".