644686262870 has 64 divisors (see below), whose sum is σ = 1257401384064. Its totient is φ = 236572047360.

The previous prime is 644686262863. The next prime is 644686262911. The reversal of 644686262870 is 78262686446.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99470030 + ... + 99476510.

It is an arithmetic number, because the mean of its divisors is an integer number (19646896626).

Almost surely, 2^644686262870 is an apocalyptic number.

644686262870 is a deficient number, since it is larger than the sum of its proper divisors (612715121194).

644686262870 is a wasteful number, since it uses less digits than its factorization.

644686262870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11097.

The product of its (nonzero) digits is 37158912, while the sum is 59.

The spelling of 644686262870 in words is "six hundred forty-four billion, six hundred eighty-six million, two hundred sixty-two thousand, eight hundred seventy".