644899487 has 2 divisors, whose sum is σ = 644899488. Its totient is φ = 644899486.

The previous prime is 644899433. The next prime is 644899517. The reversal of 644899487 is 784998446.

644899487 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 644899487 - 2²⁶ = 577790623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644899687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322449743 + 322449744.

It is an arithmetic number, because the mean of its divisors is an integer number (322449744).

Almost surely, 2^644899487 is an apocalyptic number.

644899487 is a deficient number, since it is larger than the sum of its proper divisors (1).

644899487 is an equidigital number, since it uses as much as digits as its factorization.

644899487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13934592, while the sum is 59.

The square root of 644899487 is about 25394.8712735466. The cubic root of 644899487 is about 863.9673765796.

The spelling of 644899487 in words is "six hundred forty-four million, eight hundred ninety-nine thousand, four hundred eighty-seven".