68905021 has 2 divisors, whose sum is σ = 68905022. Its totient is φ = 68905020.

The previous prime is 68905019. The next prime is 68905069. The reversal of 68905021 is 12050986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48302500 + 20602521 = 6950^2 + 4539^2 .

It is a cyclic number.

It is not a de Polignac number, because 68905021 - 2¹ = 68905019 is a prime.

Together with 68905019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68905091) 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, 34452510 + 34452511.

It is an arithmetic number, because the mean of its divisors is an integer number (34452511).

Almost surely, 2^68905021 is an apocalyptic number.

It is an amenable number.

68905021 is a deficient number, since it is larger than the sum of its proper divisors (1).

68905021 is an equidigital number, since it uses as much as digits as its factorization.

68905021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 68905021 is about 8300.9048301977. The cubic root of 68905021 is about 409.9683120463.

It can be divided in two parts, 6890 and 5021, that added together give a palindrome (11911).

The spelling of 68905021 in words is "sixty-eight million, nine hundred five thousand, twenty-one".