21121111212021 has 8 divisors (see below), whose sum is σ = 31290535128960. Its totient is φ = 14080740807996.

The previous prime is 21121111211987. The next prime is 21121111212031. The reversal of 21121111212021 is 12021211112112.

It is a happy number.

21121111212021 is a `hidden beast` number, since 211 + 211 + 11 + 212 + 0 + 21 = 666.

It is not a de Polignac number, because 21121111212021 - 2⁶ = 21121111211957 is a prime.

It is a super-2 number, since 2×21121111212021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121111211985 and 21121111212003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111212031) 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, 391131689085 + ... + 391131689138.

It is an arithmetic number, because the mean of its divisors is an integer number (3911316891120).

Almost surely, 2^{21121111212021} is an apocalyptic number.

It is an amenable number.

21121111212021 is a deficient number, since it is larger than the sum of its proper divisors (10169423916939).

21121111212021 is an equidigital number, since it uses as much as digits as its factorization.

21121111212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782263378232 (or 782263378226 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21121111212021 its reverse (12021211112112), we get a palindrome (33142322324133).

Subtracting from 21121111212021 its reverse (12021211112112), we obtain a palindrome (9099900099909).

The spelling of 21121111212021 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two hundred twelve thousand, twenty-one".