68681640 has 64 divisors (see below), whose sum is σ = 209952000. Its totient is φ = 17967872.

The previous prime is 68681629. The next prime is 68681651. The reversal of 68681640 is 4618686.

It is an interprime number because it is at equal distance from previous prime (68681629) and next prime (68681651).

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, 961 + ... + 11759.

It is an arithmetic number, because the mean of its divisors is an integer number (3280500).

Almost surely, 2^68681640 is an apocalyptic number.

68681640 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 68681640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104976000).

68681640 is an abundant number, since it is smaller than the sum of its proper divisors (141270360).

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

68681640 is a wasteful number, since it uses less digits than its factorization.

68681640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10866 (or 10862 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 68681640 is about 8287.4386875560. The cubic root of 68681640 is about 409.5248113585.

The spelling of 68681640 in words is "sixty-eight million, six hundred eighty-one thousand, six hundred forty".