644484877 has 2 divisors, whose sum is σ = 644484878. Its totient is φ = 644484876.

The previous prime is 644484871. The next prime is 644484881. The reversal of 644484877 is 778484446.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 639381796 + 5103081 = 25286^2 + 2259^2 .

It is a cyclic number.

It is not a de Polignac number, because 644484877 - 2¹⁹ = 643960589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644484871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322242438 + 322242439.

It is an arithmetic number, because the mean of its divisors is an integer number (322242439).

Almost surely, 2^644484877 is an apocalyptic number.

It is an amenable number.

644484877 is a deficient number, since it is larger than the sum of its proper divisors (1).

644484877 is an equidigital number, since it uses as much as digits as its factorization.

644484877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4816896, while the sum is 52.

The square root of 644484877 is about 25386.7066985854. The cubic root of 644484877 is about 863.7821868388.

The spelling of 644484877 in words is "six hundred forty-four million, four hundred eighty-four thousand, eight hundred seventy-seven".