20780173 has 2 divisors, whose sum is σ = 20780174. Its totient is φ = 20780172.

The previous prime is 20780143. The next prime is 20780183. The reversal of 20780173 is 37108702.

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., 20766249 + 13924 = 4557^2 + 118^2 .

It is a cyclic number.

It is not a de Polignac number, because 20780173 - 2⁵ = 20780141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20780113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10390086 + 10390087.

It is an arithmetic number, because the mean of its divisors is an integer number (10390087).

Almost surely, 2^20780173 is an apocalyptic number.

It is an amenable number.

20780173 is a deficient number, since it is larger than the sum of its proper divisors (1).

20780173 is an equidigital number, since it uses as much as digits as its factorization.

20780173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 20780173 is about 4558.5275034818. The cubic root of 20780173 is about 274.9263626529.

Adding to 20780173 its reverse (37108702), we get a palindrome (57888875).

The spelling of 20780173 in words is "twenty million, seven hundred eighty thousand, one hundred seventy-three".