21121102021009 has 4 divisors (see below), whose sum is σ = 21122266185216. Its totient is φ = 21119937856804.

The previous prime is 21121102020989. The next prime is 21121102021039. The reversal of 21121102021009 is 90012020112112.

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 21121102021009 - 2¹⁵ = 21121101988241 is a prime.

It is a super-2 number, since 2×21121102021009² (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 (21121102021039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 582054889 + ... + 582091174.

It is an arithmetic number, because the mean of its divisors is an integer number (5280566546304).

Almost surely, 2^{21121102021009} is an apocalyptic number.

It is an amenable number.

21121102021009 is a deficient number, since it is larger than the sum of its proper divisors (1164164207).

21121102021009 is a wasteful number, since it uses less digits than its factorization.

21121102021009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164164206.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21121102021009 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred two million, twenty-one thousand, nine".