68666640 has 120 divisors (see below), whose sum is σ = 247662720. Its totient is φ = 15692544.

The previous prime is 68666639. The next prime is 68666651. The reversal of 68666640 is 4666686.

It is a tau number, because it is divible by the number of its divisors (120).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 68666592 and 68666601.

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, 8841 + ... + 14679.

It is an arithmetic number, because the mean of its divisors is an integer number (2063856).

Almost surely, 2^68666640 is an apocalyptic number.

68666640 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 68666640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123831360).

68666640 is an abundant number, since it is smaller than the sum of its proper divisors (178996080).

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

68666640 is a wasteful number, since it uses less digits than its factorization.

68666640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5869 (or 5856 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 68666640 is about 8286.5336540679. The cubic root of 68666640 is about 409.4949959210.

The spelling of 68666640 in words is "sixty-eight million, six hundred sixty-six thousand, six hundred forty".