68138784 has 144 divisors (see below), whose sum is σ = 224969472. Its totient is φ = 19160064.

The previous prime is 68138747. The next prime is 68138803. The reversal of 68138784 is 48783186.

It is a tau number, because it is divible by the number of its divisors (144).

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

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, 146937 + ... + 147399.

It is an arithmetic number, because the mean of its divisors is an integer number (1562288).

Almost surely, 2^68138784 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 68138784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112484736).

68138784 is an abundant number, since it is smaller than the sum of its proper divisors (156830688).

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

68138784 is a wasteful number, since it uses less digits than its factorization.

68138784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559 (or 548 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 68138784 is about 8254.6219780193. The cubic root of 68138784 is about 408.4430020946.

The spelling of 68138784 in words is "sixty-eight million, one hundred thirty-eight thousand, seven hundred eighty-four".