581637426640 has 20 divisors (see below), whose sum is σ = 1352307017124. Its totient is φ = 232654970624.

The previous prime is 581637426631. The next prime is 581637426647. The reversal of 581637426640 is 46624736185.

It can be written as a sum of positive squares in 2 ways, for example, as 190717370944 + 390920055696 = 436712^2 + 625236^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (581637426647) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3635233837 + ... + 3635233996.

Almost surely, 2^581637426640 is an apocalyptic number.

It is an amenable number.

581637426640 is an abundant number, since it is smaller than the sum of its proper divisors (770669590484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

581637426640 is a wasteful number, since it uses less digits than its factorization.

581637426640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7270467846 (or 7270467840 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 52.

The spelling of 581637426640 in words is "five hundred eighty-one billion, six hundred thirty-seven million, four hundred twenty-six thousand, six hundred forty".