68391540 has 240 divisors, whose sum is σ = 253368192. Its totient is φ = 15116544.

The previous prime is 68391539. The next prime is 68391601. The reversal of 68391540 is 4519386.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 68391495 and 68391504.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 419499 + ... + 419661.

Almost surely, 2^68391540 is an apocalyptic number.

68391540 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 68391540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126684096).

68391540 is an abundant number, since it is smaller than the sum of its proper divisors (184976652).

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

68391540 is a wasteful number, since it uses less digits than its factorization.

68391540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 68391540 is about 8269.9177746819. The cubic root of 68391540 is about 408.9474090632.

The spelling of 68391540 in words is "sixty-eight million, three hundred ninety-one thousand, five hundred forty".