21023110331021 has 4 divisors (see below), whose sum is σ = 21024344605692. Its totient is φ = 21021876056352.

The previous prime is 21023110330967. The next prime is 21023110331039. The reversal of 21023110331021 is 12013301132012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6204652555396 + 14818457775625 = 2490914^2 + 3849475^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21023110331021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21023110330984 and 21023110331002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023110231021) 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, 617111786 + ... + 617145851.

It is an arithmetic number, because the mean of its divisors is an integer number (5256086151423).

Almost surely, 2^{21023110331021} is an apocalyptic number.

It is an amenable number.

21023110331021 is a deficient number, since it is larger than the sum of its proper divisors (1234274671).

21023110331021 is a wasteful number, since it uses less digits than its factorization.

21023110331021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234274670.

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 21023110331021 its reverse (12013301132012), we get a palindrome (33036411463033).

The spelling of 21023110331021 in words is "twenty-one trillion, twenty-three billion, one hundred ten million, three hundred thirty-one thousand, twenty-one".