644072147 has 2 divisors, whose sum is σ = 644072148. Its totient is φ = 644072146.

The previous prime is 644072113. The next prime is 644072173. The reversal of 644072147 is 741270446.

644072147 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644072147 - 2²⁰ = 643023571 is a prime.

It is not a weakly prime, because it can be changed into another prime (644072747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322036073 + 322036074.

It is an arithmetic number, because the mean of its divisors is an integer number (322036074).

Almost surely, 2^644072147 is an apocalyptic number.

644072147 is a deficient number, since it is larger than the sum of its proper divisors (1).

644072147 is an equidigital number, since it uses as much as digits as its factorization.

644072147 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 35.

The square root of 644072147 is about 25378.5765361259. The cubic root of 644072147 is about 863.5977579174.

It can be divided in two parts, 6440 and 72147, that added together give a palindrome (78587).

The spelling of 644072147 in words is "six hundred forty-four million, seventy-two thousand, one hundred forty-seven".