21112100021 has 8 divisors (see below), whose sum is σ = 22989583200. Its totient is φ = 19311248880.

The previous prime is 21112100017. The next prime is 21112100101. The reversal of 21112100021 is 12000121112.

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

It is not a de Polignac number, because 21112100021 - 2² = 21112100017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21112099975 and 21112100011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112106021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19157435 + ... + 19158536.

It is an arithmetic number, because the mean of its divisors is an integer number (2873697900).

Almost surely, 2^21112100021 is an apocalyptic number.

It is an amenable number.

21112100021 is a deficient number, since it is larger than the sum of its proper divisors (1877483179).

21112100021 is a wasteful number, since it uses less digits than its factorization.

21112100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38316019.

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

Adding to 21112100021 its reverse (12000121112), we get a palindrome (33112221133).

The spelling of 21112100021 in words is "twenty-one billion, one hundred twelve million, one hundred thousand, twenty-one".