21212211329 has 4 divisors (see below), whose sum is σ = 22459988484. Its totient is φ = 19964434176.

The previous prime is 21212211299. The next prime is 21212211331. The reversal of 21212211329 is 92311221212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9125407729 + 12086803600 = 95527^2 + 109940^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212211329 - 2⁸ = 21212211073 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212211298 and 21212211307.

It is not an unprimeable number, because it can be changed into a prime (21212211379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 623888552 + ... + 623888585.

It is an arithmetic number, because the mean of its divisors is an integer number (5614997121).

Almost surely, 2^21212211329 is an apocalyptic number.

It is an amenable number.

21212211329 is a deficient number, since it is larger than the sum of its proper divisors (1247777155).

21212211329 is a wasteful number, since it uses less digits than its factorization.

21212211329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247777154.

The product of its digits is 864, while the sum is 26.

The spelling of 21212211329 in words is "twenty-one billion, two hundred twelve million, two hundred eleven thousand, three hundred twenty-nine".