21210011021 has 8 divisors (see below), whose sum is σ = 21348942720. Its totient is φ = 21071187072.

The previous prime is 21210010937. The next prime is 21210011023. The reversal of 21210011021 is 12011001212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21210011021 - 2¹⁸ = 21209748877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210010993 and 21210011011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210011023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 388925 + ... + 440093.

It is an arithmetic number, because the mean of its divisors is an integer number (2668617840).

Almost surely, 2^21210011021 is an apocalyptic number.

It is an amenable number.

21210011021 is a deficient number, since it is larger than the sum of its proper divisors (138931699).

21210011021 is a wasteful number, since it uses less digits than its factorization.

21210011021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53875.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21210011021 its reverse (12011001212), we get a palindrome (33221012233).

The spelling of 21210011021 in words is "twenty-one billion, two hundred ten million, eleven thousand, twenty-one".