21121011122009 has 4 divisors (see below), whose sum is σ = 21612197427216. Its totient is φ = 20629824816804.

The previous prime is 21121011121961. The next prime is 21121011122087. The reversal of 21121011122009 is 90022111012112.

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 21121011122009 - 2²⁸ = 21120742686553 is a prime.

It is a super-2 number, since 2×21121011122009² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121011122209) 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, 245593152539 + ... + 245593152624.

It is an arithmetic number, because the mean of its divisors is an integer number (5403049356804).

Almost surely, 2^{21121011122009} is an apocalyptic number.

It is an amenable number.

21121011122009 is a deficient number, since it is larger than the sum of its proper divisors (491186305207).

21121011122009 is an equidigital number, since it uses as much as digits as its factorization.

21121011122009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491186305206.

The product of its (nonzero) digits is 144, while the sum is 23.

The spelling of 21121011122009 in words is "twenty-one trillion, one hundred twenty-one billion, eleven million, one hundred twenty-two thousand, nine".