21311211210021 has 24 divisors (see below), whose sum is σ = 32643993829824. Its totient is φ = 13351073009280.

The previous prime is 21311211210019. The next prime is 21311211210031. The reversal of 21311211210021 is 12001211211312.

It is a happy number.

21311211210021 is a `hidden beast` number, since 21 + 311 + 211 + 2 + 100 + 21 = 666.

It is not a de Polignac number, because 21311211210021 - 2¹ = 21311211210019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311211209976 and 21311211210003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311211210011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107543175 + ... + 107741156.

It is an arithmetic number, because the mean of its divisors is an integer number (1360166409576).

Almost surely, 2^{21311211210021} is an apocalyptic number.

It is an amenable number.

21311211210021 is a deficient number, since it is larger than the sum of its proper divisors (11332782619803).

21311211210021 is a wasteful number, since it uses less digits than its factorization.

21311211210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215285001 (or 215284998 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 21311211210021 its reverse (12001211211312), we get a palindrome (33312422421333).

The spelling of 21311211210021 in words is "twenty-one trillion, three hundred eleven billion, two hundred eleven million, two hundred ten thousand, twenty-one".