644507302605 has 64 divisors (see below), whose sum is σ = 1116669058560. Its totient is φ = 316451480576.

The previous prime is 644507302583. The next prime is 644507302679. The reversal of 644507302605 is 506203705446.

It is a cyclic number.

It is not a de Polignac number, because 644507302605 - 2⁹ = 644507302093 is a prime.

It is a super-2 number, since 2×644507302605² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3069979 + ... + 3273191.

It is an arithmetic number, because the mean of its divisors is an integer number (17447954040).

Almost surely, 2^644507302605 is an apocalyptic number.

It is an amenable number.

644507302605 is a deficient number, since it is larger than the sum of its proper divisors (472161755955).

644507302605 is a wasteful number, since it uses less digits than its factorization.

644507302605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203590.

The product of its (nonzero) digits is 604800, while the sum is 42.

The spelling of 644507302605 in words is "six hundred forty-four billion, five hundred seven million, three hundred two thousand, six hundred five".