68661720 has 96 divisors (see below), whose sum is σ = 225763200. Its totient is φ = 18095616.

The previous prime is 68661713. The next prime is 68661727. The reversal of 68661720 is 2716686.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (68661713) and next prime (68661727).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68661727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30969 + ... + 33111.

It is an arithmetic number, because the mean of its divisors is an integer number (2351700).

Almost surely, 2^68661720 is an apocalyptic number.

68661720 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 68661720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112881600).

68661720 is an abundant number, since it is smaller than the sum of its proper divisors (157101480).

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

68661720 is a wasteful number, since it uses less digits than its factorization.

68661720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2249 (or 2242 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 68661720 is about 8286.2367815553. The cubic root of 68661720 is about 409.4852155119.

The spelling of 68661720 in words is "sixty-eight million, six hundred sixty-one thousand, seven hundred twenty".