20623181 has 2 divisors, whose sum is σ = 20623182. Its totient is φ = 20623180.

The previous prime is 20623139. The next prime is 20623217. The reversal of 20623181 is 18132602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20620681 + 2500 = 4541^2 + 50^2 .

It is a cyclic number.

It is not a de Polignac number, because 20623181 - 2⁶ = 20623117 is a prime.

It is a super-2 number, since 2×20623181² = 850631189117522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20623121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10311590 + 10311591.

It is an arithmetic number, because the mean of its divisors is an integer number (10311591).

Almost surely, 2^20623181 is an apocalyptic number.

It is an amenable number.

20623181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20623181 is an equidigital number, since it uses as much as digits as its factorization.

20623181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 20623181 is about 4541.2752614216. The cubic root of 20623181 is about 274.2322652730.

Adding to 20623181 its reverse (18132602), we get a palindrome (38755783).

The spelling of 20623181 in words is "twenty million, six hundred twenty-three thousand, one hundred eighty-one".