12111001021 has 4 divisors (see below), whose sum is σ = 13841144032. Its totient is φ = 10380858012.

The previous prime is 12111000989. The next prime is 12111001039. The reversal of 12111001021 is 12010011121.

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: 12010011121 = 50087 ⋅239783.

It is not a de Polignac number, because 12111001021 - 2⁵ = 12111000989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12111000989 and 12111001007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12111001081) 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, 865071495 + ... + 865071508.

It is an arithmetic number, because the mean of its divisors is an integer number (3460286008).

Almost surely, 2^12111001021 is an apocalyptic number.

It is an amenable number.

12111001021 is a deficient number, since it is larger than the sum of its proper divisors (1730143011).

12111001021 is an equidigital number, since it uses as much as digits as its factorization.

12111001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1730143010.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 12111001021 its reverse (12010011121), we get a palindrome (24121012142).

It can be divided in two parts, 1211100 and 1021, that added together give a palindrome (1212121).

The spelling of 12111001021 in words is "twelve billion, one hundred eleven million, one thousand, twenty-one".