641738989656 has 96 divisors (see below), whose sum is σ = 1808175292560. Its totient is φ = 213229366272.

The previous prime is 641738989637. The next prime is 641738989667. The reversal of 641738989656 is 656989837146.

641738989656 is a `hidden beast` number, since 6 + 417 + 3 + 89 + 89 + 6 + 56 = 666.

641738989656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81136 + ... + 1135808.

Almost surely, 2^641738989656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641738989656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (904087646280).

641738989656 is an abundant number, since it is smaller than the sum of its proper divisors (1166436302904).

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

641738989656 is a wasteful number, since it uses less digits than its factorization.

641738989656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055007 (or 1054991 counting only the distinct ones).

The product of its digits is 470292480, while the sum is 72.

The spelling of 641738989656 in words is "six hundred forty-one billion, seven hundred thirty-eight million, nine hundred eighty-nine thousand, six hundred fifty-six".