644352025 has 6 divisors (see below), whose sum is σ = 798996542. Its totient is φ = 515481600.

The previous prime is 644352013. The next prime is 644352029. The reversal of 644352025 is 520253446.

It can be written as a sum of positive squares in 3 ways, for example, as 12131289 + 632220736 = 3483^2 + 25144^2 .

It is not a de Polignac number, because 644352025 - 2¹¹ = 644349977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644352029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12887016 + ... + 12887065.

Almost surely, 2^644352025 is an apocalyptic number.

It is an amenable number.

644352025 is a deficient number, since it is larger than the sum of its proper divisors (154644517).

644352025 is a wasteful number, since it uses less digits than its factorization.

644352025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25774091 (or 25774086 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 31.

The square root of 644352025 is about 25384.0899974768. The cubic root of 644352025 is about 863.7228303505.

The spelling of 644352025 in words is "six hundred forty-four million, three hundred fifty-two thousand, twenty-five".