20123021 has 2 divisors, whose sum is σ = 20123022. Its totient is φ = 20123020.

The previous prime is 20123017. The next prime is 20123029. The reversal of 20123021 is 12032102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16933225 + 3189796 = 4115^2 + 1786^2 .

It is a cyclic number.

It is not a de Polignac number, because 20123021 - 2² = 20123017 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20122993 and 20123011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20123029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10061510 + 10061511.

It is an arithmetic number, because the mean of its divisors is an integer number (10061511).

Almost surely, 2^20123021 is an apocalyptic number.

It is an amenable number.

20123021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20123021 is an equidigital number, since it uses as much as digits as its factorization.

20123021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 20123021 is about 4485.8690350923. The cubic root of 20123021 is about 271.9971750355.

Adding to 20123021 its reverse (12032102), we get a palindrome (32155123).

The spelling of 20123021 in words is "twenty million, one hundred twenty-three thousand, twenty-one".