67641920640 has 960 divisors, whose sum is σ = 290402323200. Its totient is φ = 14944849920.

The previous prime is 67641920573. The next prime is 67641920641. The reversal of 67641920640 is 4602914676.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (67641920641) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 78744531 + ... + 78745389.

It is an arithmetic number, because the mean of its divisors is an integer number (302502420).

Almost surely, 2^67641920640 is an apocalyptic number.

67641920640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 67641920640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145201161600).

67641920640 is an abundant number, since it is smaller than the sum of its proper divisors (222760402560).

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

67641920640 is a wasteful number, since it uses less digits than its factorization.

67641920640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 67641920640 in words is "sixty-seven billion, six hundred forty-one million, nine hundred twenty thousand, six hundred forty".