644145066 has 24 divisors (see below), whose sum is σ = 1400147424. Its totient is φ = 214022760.

The previous prime is 644145023. The next prime is 644145077. The reversal of 644145066 is 660541446.

644145066 is a `hidden beast` number, since 644 + 1 + 4 + 5 + 0 + 6 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 644145066.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51936 + ... + 63131.

It is an arithmetic number, because the mean of its divisors is an integer number (58339476).

Almost surely, 2^644145066 is an apocalyptic number.

644145066 is an abundant number, since it is smaller than the sum of its proper divisors (756002358).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644145066 is a wasteful number, since it uses less digits than its factorization.

644145066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115386 (or 115383 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 644145066 is about 25380.0131205640. The cubic root of 644145066 is about 863.6303475938.

The spelling of 644145066 in words is "six hundred forty-four million, one hundred forty-five thousand, sixty-six".