68921440 has 144 divisors (see below), whose sum is σ = 193914000. Its totient is φ = 23073792.

The previous prime is 68921407. The next prime is 68921441. The reversal of 68921440 is 4412986.

It is a junction number, because it is equal to n+sod(n) for n = 68921396 and 68921405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68921441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 462486 + ... + 462634.

It is an arithmetic number, because the mean of its divisors is an integer number (1346625).

Almost surely, 2^68921440 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 68921440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96957000).

68921440 is an abundant number, since it is smaller than the sum of its proper divisors (124992560).

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

68921440 is a wasteful number, since it uses less digits than its factorization.

68921440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 68921440 is about 8301.8937598599. The cubic root of 68921440 is about 410.0008724947. Note that the first 3 decimals are identical.

The spelling of 68921440 in words is "sixty-eight million, nine hundred twenty-one thousand, four hundred forty".