21212202102021 has 24 divisors (see below), whose sum is σ = 35073722209344. Its totient is φ = 12101612846400.

The previous prime is 21212202102011. The next prime is 21212202102023. The reversal of 21212202102021 is 12020120221212.

It is a happy number.

21212202102021 is a `hidden beast` number, since 21 + 212 + 20 + 210 + 202 + 1 = 666.

It is not a de Polignac number, because 21212202102021 - 2²⁹ = 21211665231109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212202101985 and 21212202102003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212202102023) 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, 272814955 + ... + 272892696.

It is an arithmetic number, because the mean of its divisors is an integer number (1461405092056).

Almost surely, 2^{21212202102021} is an apocalyptic number.

21212202102021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21212202102021 is a deficient number, since it is larger than the sum of its proper divisors (13861520107323).

21212202102021 is a wasteful number, since it uses less digits than its factorization.

21212202102021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545708281 (or 545708278 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21212202102021 its reverse (12020120221212), we get a palindrome (33232322323233).

The spelling of 21212202102021 in words is "twenty-one trillion, two hundred twelve billion, two hundred two million, one hundred two thousand, twenty-one".