21121123013 has 4 divisors (see below), whose sum is σ = 21121680288. Its totient is φ = 21120565740.

The previous prime is 21121123003. The next prime is 21121123027. The reversal of 21121123013 is 31032112112.

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 21121123013 - 2¹² = 21121118917 is a prime.

It is a super-2 number, since 2×21121123013² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121122982 and 21121123000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121123003) 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, 217283 + ... + 299088.

It is an arithmetic number, because the mean of its divisors is an integer number (5280420072).

Almost surely, 2^21121123013 is an apocalyptic number.

It is an amenable number.

21121123013 is a deficient number, since it is larger than the sum of its proper divisors (557275).

21121123013 is an equidigital number, since it uses as much as digits as its factorization.

21121123013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557274.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21121123013 its reverse (31032112112), we get a palindrome (52153235125).

The spelling of 21121123013 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty-three thousand, thirteen".