12120020021 has 4 divisors (see below), whose sum is σ = 12138753312. Its totient is φ = 12101286732.

The previous prime is 12120020009. The next prime is 12120020023. The reversal of 12120020021 is 12002002121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12002002121 = 139 ⋅86345339.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12120020021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 12120019984 and 12120020011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12120020023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9365675 + ... + 9366968.

It is an arithmetic number, because the mean of its divisors is an integer number (3034688328).

Almost surely, 2^12120020021 is an apocalyptic number.

It is an amenable number.

12120020021 is a deficient number, since it is larger than the sum of its proper divisors (18733291).

12120020021 is an equidigital number, since it uses as much as digits as its factorization.

12120020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18733290.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 12120020021 its reverse (12002002121), we get a palindrome (24122022142).

The spelling of 12120020021 in words is "twelve billion, one hundred twenty million, twenty thousand, twenty-one".