68707921 has 2 divisors, whose sum is σ = 68707922. Its totient is φ = 68707920.

The previous prime is 68707909. The next prime is 68707939. The reversal of 68707921 is 12970786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68707521 + 400 = 8289^2 + 20^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68707921 is a prime.

It is not a weakly prime, because it can be changed into another prime (68707321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34353960 + 34353961.

It is an arithmetic number, because the mean of its divisors is an integer number (34353961).

Almost surely, 2^68707921 is an apocalyptic number.

It is an amenable number.

68707921 is a deficient number, since it is larger than the sum of its proper divisors (1).

68707921 is an equidigital number, since it uses as much as digits as its factorization.

68707921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 68707921 is about 8289.0241283278. The cubic root of 68707921 is about 409.5770395283.

The spelling of 68707921 in words is "sixty-eight million, seven hundred seven thousand, nine hundred twenty-one".