20778937 has 2 divisors, whose sum is σ = 20778938. Its totient is φ = 20778936.

The previous prime is 20778887. The next prime is 20778973. The reversal of 20778937 is 73987702.

Together with next prime (20778973) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17172736 + 3606201 = 4144^2 + 1899^2 .

It is a cyclic number.

It is not a de Polignac number, because 20778937 - 2¹⁹ = 20254649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20778893 and 20778902.

It is not a weakly prime, because it can be changed into another prime (20779937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10389468 + 10389469.

It is an arithmetic number, because the mean of its divisors is an integer number (10389469).

Almost surely, 2^20778937 is an apocalyptic number.

It is an amenable number.

20778937 is a deficient number, since it is larger than the sum of its proper divisors (1).

20778937 is an equidigital number, since it uses as much as digits as its factorization.

20778937 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 20778937 is about 4558.3919313723. The cubic root of 20778937 is about 274.9209116921.

The spelling of 20778937 in words is "twenty million, seven hundred seventy-eight thousand, nine hundred thirty-seven".