68321664 has 128 divisors (see below), whose sum is σ = 205999200. Its totient is φ = 22284288.

The previous prime is 68321653. The next prime is 68321681. The reversal of 68321664 is 46612386.

It is a tau number, because it is divible by the number of its divisors (128).

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

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 15 ways as a sum of consecutive naturals, for example, 182982 + ... + 183354.

Almost surely, 2^68321664 is an apocalyptic number.

68321664 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 68321664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102999600).

68321664 is an abundant number, since it is smaller than the sum of its proper divisors (137677536).

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

68321664 is a wasteful number, since it uses less digits than its factorization.

68321664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449 (or 431 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 68321664 is about 8265.6919855509. The cubic root of 68321664 is about 408.8080870231.

The spelling of 68321664 in words is "sixty-eight million, three hundred twenty-one thousand, six hundred sixty-four".