21120022120021 has 4 divisors (see below), whose sum is σ = 23040024130944. Its totient is φ = 19200020109100.

The previous prime is 21120022120003. The next prime is 21120022120051. The reversal of 21120022120021 is 12002122002112.

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 21120022120021 - 2¹⁹ = 21120021595733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120022119977 and 21120022120004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120022120051) 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, 960001005445 + ... + 960001005466.

It is an arithmetic number, because the mean of its divisors is an integer number (5760006032736).

Almost surely, 2^{21120022120021} is an apocalyptic number.

It is an amenable number.

21120022120021 is a deficient number, since it is larger than the sum of its proper divisors (1920002010923).

21120022120021 is a wasteful number, since it uses less digits than its factorization.

21120022120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920002010922.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21120022120021 its reverse (12002122002112), we get a palindrome (33122144122133).

The spelling of 21120022120021 in words is "twenty-one trillion, one hundred twenty billion, twenty-two million, one hundred twenty thousand, twenty-one".