68021381 has 2 divisors, whose sum is σ = 68021382. Its totient is φ = 68021380.

The previous prime is 68021377. The next prime is 68021383. The reversal of 68021381 is 18312086.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56400100 + 11621281 = 7510^2 + 3409^2 .

It is a cyclic number.

It is not a de Polignac number, because 68021381 - 2² = 68021377 is a prime.

It is a super-2 number, since 2×68021381² = 9253816546294322, which contains 22 as substring.

Together with 68021383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68021383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34010690 + 34010691.

It is an arithmetic number, because the mean of its divisors is an integer number (34010691).

Almost surely, 2^68021381 is an apocalyptic number.

It is an amenable number.

68021381 is a deficient number, since it is larger than the sum of its proper divisors (1).

68021381 is an equidigital number, since it uses as much as digits as its factorization.

68021381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 68021381 is about 8247.5075628944. The cubic root of 68021381 is about 408.2082850558.

The spelling of 68021381 in words is "sixty-eight million, twenty-one thousand, three hundred eighty-one".