644676953371 has 16 divisors (see below), whose sum is σ = 720490927968. Its totient is φ = 571732940800.

The previous prime is 644676953369. The next prime is 644676953387. The reversal of 644676953371 is 173359676446.

It is a cyclic number.

It is not a de Polignac number, because 644676953371 - 2¹ = 644676953369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644676953311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7051971 + ... + 7142803.

It is an arithmetic number, because the mean of its divisors is an integer number (45030682998).

Almost surely, 2^644676953371 is an apocalyptic number.

644676953371 is a deficient number, since it is larger than the sum of its proper divisors (75813974597).

644676953371 is a wasteful number, since it uses less digits than its factorization.

644676953371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106622.

The product of its digits is 68584320, while the sum is 61.

The spelling of 644676953371 in words is "six hundred forty-four billion, six hundred seventy-six million, nine hundred fifty-three thousand, three hundred seventy-one".