644587245 has 12 divisors (see below), whose sum is σ = 1117284636. Its totient is φ = 343779840.

The previous prime is 644587241. The next prime is 644587253. The reversal of 644587245 is 542785446.

644587245 is a `hidden beast` number, since 6 + 44 + 587 + 24 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 378146916 + 266440329 = 19446^2 + 16323^2 .

It is not a de Polignac number, because 644587245 - 2² = 644587241 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 14324161 = 644587245 / (6 + 4 + 4 + 5 + 8 + 7 + 2 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 644587245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644587241) 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 11 ways as a sum of consecutive naturals, for example, 7162036 + ... + 7162125.

It is an arithmetic number, because the mean of its divisors is an integer number (93107053).

Almost surely, 2^644587245 is an apocalyptic number.

It is an amenable number.

644587245 is a deficient number, since it is larger than the sum of its proper divisors (472697391).

644587245 is a wasteful number, since it uses less digits than its factorization.

644587245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14324172 (or 14324169 counting only the distinct ones).

The product of its digits is 1075200, while the sum is 45.

The square root of 644587245 is about 25388.7227918224. The cubic root of 644587245 is about 863.8279179215.

The spelling of 644587245 in words is "six hundred forty-four million, five hundred eighty-seven thousand, two hundred forty-five".