68721551 has 2 divisors, whose sum is σ = 68721552. Its totient is φ = 68721550.

The previous prime is 68721533. The next prime is 68721571. The reversal of 68721551 is 15512786.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68721551 - 2⁶ = 68721487 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68721571) 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 as a sum of consecutive naturals, namely, 34360775 + 34360776.

It is an arithmetic number, because the mean of its divisors is an integer number (34360776).

Almost surely, 2^68721551 is an apocalyptic number.

68721551 is a deficient number, since it is larger than the sum of its proper divisors (1).

68721551 is an equidigital number, since it uses as much as digits as its factorization.

68721551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16800, while the sum is 35.

The square root of 68721551 is about 8289.8462591293. The cubic root of 68721551 is about 409.6041211508.

The spelling of 68721551 in words is "sixty-eight million, seven hundred twenty-one thousand, five hundred fifty-one".