20668777 has 2 divisors, whose sum is σ = 20668778. Its totient is φ = 20668776.

The previous prime is 20668771. The next prime is 20668799. The reversal of 20668777 is 77786602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14017536 + 6651241 = 3744^2 + 2579^2 .

It is a cyclic number.

It is not a de Polignac number, because 20668777 - 2¹⁵ = 20636009 is a prime.

It is not a weakly prime, because it can be changed into another prime (20668771) 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, 10334388 + 10334389.

It is an arithmetic number, because the mean of its divisors is an integer number (10334389).

Almost surely, 2^20668777 is an apocalyptic number.

It is an amenable number.

20668777 is a deficient number, since it is larger than the sum of its proper divisors (1).

20668777 is an equidigital number, since it uses as much as digits as its factorization.

20668777 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 197568, while the sum is 43.

The square root of 20668777 is about 4546.2926654583. The cubic root of 20668777 is about 274.4342174787.

The spelling of 20668777 in words is "twenty million, six hundred sixty-eight thousand, seven hundred seventy-seven".