820123001 has 2 divisors, whose sum is σ = 820123002. Its totient is φ = 820123000.

The previous prime is 820122991. The next prime is 820123013. The reversal of 820123001 is 100321028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 815388025 + 4734976 = 28555^2 + 2176^2 .

It is a cyclic number.

It is not a de Polignac number, because 820123001 - 2¹⁰ = 820121977 is a prime.

It is not a weakly prime, because it can be changed into another prime (820126001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410061500 + 410061501.

It is an arithmetic number, because the mean of its divisors is an integer number (410061501).

Almost surely, 2^820123001 is an apocalyptic number.

It is an amenable number.

820123001 is a deficient number, since it is larger than the sum of its proper divisors (1).

820123001 is an equidigital number, since it uses as much as digits as its factorization.

820123001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 820123001 is about 28637.7897366399. The cubic root of 820123001 is about 936.0369598629.

Adding to 820123001 its reverse (100321028), we get a palindrome (920444029).

The spelling of 820123001 in words is "eight hundred twenty million, one hundred twenty-three thousand, one".