21000131233121 has 4 divisors (see below), whose sum is σ = 21160437578544. Its totient is φ = 20839824887700.

The previous prime is 21000131233079. The next prime is 21000131233231. The reversal of 21000131233121 is 12133213100012.

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.

It is a cyclic number.

It is not a de Polignac number, because 21000131233121 - 2¹⁸ = 21000130970977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000131233093 and 21000131233102.

It is not an unprimeable number, because it can be changed into a prime (21000131233321) 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, 80153172515 + ... + 80153172776.

It is an arithmetic number, because the mean of its divisors is an integer number (5290109394636).

Almost surely, 2^{21000131233121} is an apocalyptic number.

It is an amenable number.

21000131233121 is a deficient number, since it is larger than the sum of its proper divisors (160306345423).

21000131233121 is a wasteful number, since it uses less digits than its factorization.

21000131233121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160306345422.

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

Adding to 21000131233121 its reverse (12133213100012), we get a palindrome (33133344333133).

The spelling of 21000131233121 in words is "twenty-one trillion, one hundred thirty-one million, two hundred thirty-three thousand, one hundred twenty-one".