68779021 has 2 divisors, whose sum is σ = 68779022. Its totient is φ = 68779020.

The previous prime is 68778979. The next prime is 68779027. The reversal of 68779021 is 12097786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49154121 + 19624900 = 7011^2 + 4430^2 .

It is a cyclic number.

It is not a de Polignac number, because 68779021 - 2⁹ = 68778509 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 (68779027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34389510 + 34389511.

It is an arithmetic number, because the mean of its divisors is an integer number (34389511).

Almost surely, 2^68779021 is an apocalyptic number.

It is an amenable number.

68779021 is a deficient number, since it is larger than the sum of its proper divisors (1).

68779021 is an equidigital number, since it uses as much as digits as its factorization.

68779021 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 68779021 is about 8293.3118233912. The cubic root of 68779021 is about 409.7182696705.

The spelling of 68779021 in words is "sixty-eight million, seven hundred seventy-nine thousand, twenty-one".