20700817 has 2 divisors, whose sum is σ = 20700818. Its totient is φ = 20700816.

The previous prime is 20700791. The next prime is 20700833. The reversal of 20700817 is 71800702.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12383361 + 8317456 = 3519^2 + 2884^2 .

It is a cyclic number.

It is not a de Polignac number, because 20700817 - 2¹⁹ = 20176529 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20700791 and 20700800.

It is not a weakly prime, because it can be changed into another prime (20700887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10350408 + 10350409.

It is an arithmetic number, because the mean of its divisors is an integer number (10350409).

Almost surely, 2^20700817 is an apocalyptic number.

It is an amenable number.

20700817 is a deficient number, since it is larger than the sum of its proper divisors (1).

20700817 is an equidigital number, since it uses as much as digits as its factorization.

20700817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 20700817 is about 4549.8150511861. The cubic root of 20700817 is about 274.5759503087.

It can be divided in two parts, 207008 and 17, that added together give a square (207025 = 455²).

The spelling of 20700817 in words is "twenty million, seven hundred thousand, eight hundred seventeen".