644453587 has 2 divisors, whose sum is σ = 644453588. Its totient is φ = 644453586.

The previous prime is 644453489. The next prime is 644453597. The reversal of 644453587 is 785354446.

644453587 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 a de Polignac number, because none of the positive numbers 2^k-644453587 is a prime.

It is not a weakly prime, because it can be changed into another prime (644453597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322226793 + 322226794.

It is an arithmetic number, because the mean of its divisors is an integer number (322226794).

Almost surely, 2^644453587 is an apocalyptic number.

644453587 is a deficient number, since it is larger than the sum of its proper divisors (1).

644453587 is an equidigital number, since it uses as much as digits as its factorization.

644453587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1612800, while the sum is 46.

The square root of 644453587 is about 25386.0904236946. The cubic root of 644453587 is about 863.7682076217.

It can be divided in two parts, 6444 and 53587, that added together give a triangular number (60031 = T₃₄₆).

The spelling of 644453587 in words is "six hundred forty-four million, four hundred fifty-three thousand, five hundred eighty-seven".