68661681984 has 504 divisors, whose sum is σ = 245054628000. Its totient is φ = 18271733760.

The previous prime is 68661681931. The next prime is 68661681989. The reversal of 68661681984 is 48918616686.

68661681984 is a `hidden beast` number, since 6 + 8 + 6 + 616 + 8 + 1 + 9 + 8 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68661681989) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 32710567 + ... + 32712665.

It is an arithmetic number, because the mean of its divisors is an integer number (486219500).

Almost surely, 2^68661681984 is an apocalyptic number.

68661681984 is a gapful number since it is divisible by the number (64) 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 68661681984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122527314000).

68661681984 is an abundant number, since it is smaller than the sum of its proper divisors (176392946016).

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

68661681984 is a wasteful number, since it uses less digits than its factorization.

68661681984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2211 (or 2191 counting only the distinct ones).

The product of its digits is 23887872, while the sum is 63.

The spelling of 68661681984 in words is "sixty-eight billion, six hundred sixty-one million, six hundred eighty-one thousand, nine hundred eighty-four".