20778673 has 2 divisors, whose sum is σ = 20778674. Its totient is φ = 20778672.

The previous prime is 20778623. The next prime is 20778697. The reversal of 20778673 is 37687702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10837264 + 9941409 = 3292^2 + 3153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20778673 is a prime.

It is not a weakly prime, because it can be changed into another prime (20778623) 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, 10389336 + 10389337.

It is an arithmetic number, because the mean of its divisors is an integer number (10389337).

Almost surely, 2^20778673 is an apocalyptic number.

It is an amenable number.

20778673 is a deficient number, since it is larger than the sum of its proper divisors (1).

20778673 is an equidigital number, since it uses as much as digits as its factorization.

20778673 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 98784, while the sum is 40.

The square root of 20778673 is about 4558.3629737001. The cubic root of 20778673 is about 274.9197473812.

The spelling of 20778673 in words is "twenty million, seven hundred seventy-eight thousand, six hundred seventy-three".