100405212221 has 2 divisors, whose sum is σ = 100405212222. Its totient is φ = 100405212220.

The previous prime is 100405212197. The next prime is 100405212223. The reversal of 100405212221 is 122212504001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99938176900 + 467035321 = 316130^2 + 21611^2 .

It is a cyclic number.

It is not a de Polignac number, because 100405212221 - 2¹⁰ = 100405211197 is a prime.

It is a super-2 number, since 2×100405212221² (a number of 23 digits) contains 22 as substring.

Together with 100405212223, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 100405212193 and 100405212202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100405212223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50202606110 + 50202606111.

It is an arithmetic number, because the mean of its divisors is an integer number (50202606111).

Almost surely, 2^100405212221 is an apocalyptic number.

It is an amenable number.

100405212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

100405212221 is an equidigital number, since it uses as much as digits as its factorization.

100405212221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 20.

Adding to 100405212221 its reverse (122212504001), we get a palindrome (222617716222).

The spelling of 100405212221 in words is "one hundred billion, four hundred five million, two hundred twelve thousand, two hundred twenty-one".