641136640 has 192 divisors, whose sum is σ = 1698278400. Its totient is φ = 231211008.

The previous prime is 641136631. The next prime is 641136653. The reversal of 641136640 is 46631146.

It is a super-2 number, since 2×641136640² = 822112382300979200, which 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 15 ways as a sum of consecutive naturals, for example, 5048257 + ... + 5048383.

It is an arithmetic number, because the mean of its divisors is an integer number (8845200).

Almost surely, 2^641136640 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 641136640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (849139200).

641136640 is an abundant number, since it is smaller than the sum of its proper divisors (1057141760).

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

641136640 is a wasteful number, since it uses less digits than its factorization.

641136640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 641136640 is about 25320.6761363120. The cubic root of 641136640 is about 862.2837444243.

Adding to 641136640 its reverse (46631146), we get a palindrome (687767786).

The spelling of 641136640 in words is "six hundred forty-one million, one hundred thirty-six thousand, six hundred forty".