20123861 has 2 divisors, whose sum is σ = 20123862. Its totient is φ = 20123860.

The previous prime is 20123843. The next prime is 20123881. The reversal of 20123861 is 16832102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11771761 + 8352100 = 3431^2 + 2890^2 .

It is a cyclic number.

It is not a de Polignac number, because 20123861 - 2¹⁸ = 19861717 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20123881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10061930 + 10061931.

It is an arithmetic number, because the mean of its divisors is an integer number (10061931).

Almost surely, 2^20123861 is an apocalyptic number.

It is an amenable number.

20123861 is a deficient number, since it is larger than the sum of its proper divisors (1).

20123861 is an equidigital number, since it uses as much as digits as its factorization.

20123861 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 20123861 is about 4485.9626614585. The cubic root of 20123861 is about 272.0009596636. Note that the first 3 decimals are identical.

Adding to 20123861 its reverse (16832102), we get a palindrome (36955963).

The spelling of 20123861 in words is "twenty million, one hundred twenty-three thousand, eight hundred sixty-one".