644952601 has 4 divisors (see below), whose sum is σ = 657121572. Its totient is φ = 632783632.

The previous prime is 644952599. The next prime is 644952631. The reversal of 644952601 is 106259446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 106259446 = 2 ⋅53129723.

It can be written as a sum of positive squares in 2 ways, for example, as 485056576 + 159896025 = 22024^2 + 12645^2 .

It is a cyclic number.

It is not a de Polignac number, because 644952601 - 2¹ = 644952599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644952631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6084406 + ... + 6084511.

It is an arithmetic number, because the mean of its divisors is an integer number (164280393).

Almost surely, 2^644952601 is an apocalyptic number.

It is an amenable number.

644952601 is a deficient number, since it is larger than the sum of its proper divisors (12168971).

644952601 is a wasteful number, since it uses less digits than its factorization.

644952601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12168970.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 644952601 is about 25395.9170143549. The cubic root of 644952601 is about 863.9910947477.

The spelling of 644952601 in words is "six hundred forty-four million, nine hundred fifty-two thousand, six hundred one".