68240640 has 144 divisors (see below), whose sum is σ = 234880128. Its totient is φ = 16785408.

The previous prime is 68240633. The next prime is 68240681. The reversal of 68240640 is 4604286.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 68240598 and 68240607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49237 + ... + 50603.

It is an arithmetic number, because the mean of its divisors is an integer number (1631112).

Almost surely, 2^68240640 is an apocalyptic number.

68240640 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 68240640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117440064).

68240640 is an abundant number, since it is smaller than the sum of its proper divisors (166639488).

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

68240640 is a wasteful number, since it uses less digits than its factorization.

68240640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1404 (or 1390 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 68240640 is about 8260.7893085346. The cubic root of 68240640 is about 408.6464185909.

The spelling of 68240640 in words is "sixty-eight million, two hundred forty thousand, six hundred forty".