68421640 has 64 divisors (see below), whose sum is σ = 179568000. Its totient is φ = 23454144.

The previous prime is 68421629. The next prime is 68421649. The reversal of 68421640 is 4612486.

It is not an unprimeable number, because it can be changed into a prime (68421649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11227 + ... + 16213.

It is an arithmetic number, because the mean of its divisors is an integer number (2805750).

Almost surely, 2^68421640 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 68421640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89784000).

68421640 is an abundant number, since it is smaller than the sum of its proper divisors (111146360).

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

68421640 is a wasteful number, since it uses less digits than its factorization.

68421640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5019 (or 5001 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 68421640 is about 8271.7374232987. The cubic root of 68421640 is about 409.0073946093.

The spelling of 68421640 in words is "sixty-eight million, four hundred twenty-one thousand, six hundred forty".