68842721 has 2 divisors, whose sum is σ = 68842722. Its totient is φ = 68842720.

The previous prime is 68842717. The next prime is 68842769. The reversal of 68842721 is 12724886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37650496 + 31192225 = 6136^2 + 5585^2 .

It is a cyclic number.

It is not a de Polignac number, because 68842721 - 2² = 68842717 is a prime.

It is not a weakly prime, because it can be changed into another prime (68842771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34421360 + 34421361.

It is an arithmetic number, because the mean of its divisors is an integer number (34421361).

Almost surely, 2^68842721 is an apocalyptic number.

It is an amenable number.

68842721 is a deficient number, since it is larger than the sum of its proper divisors (1).

68842721 is an equidigital number, since it uses as much as digits as its factorization.

68842721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43008, while the sum is 38.

The square root of 68842721 is about 8297.1513786359. The cubic root of 68842721 is about 409.8447181150.

The spelling of 68842721 in words is "sixty-eight million, eight hundred forty-two thousand, seven hundred twenty-one".