21020202122 has 4 divisors (see below), whose sum is σ = 31530303186. Its totient is φ = 10510101060.

The previous prime is 21020202103. The next prime is 21020202139. The reversal of 21020202122 is 22120202012.

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

It can be written as a sum of positive squares in only one way, i.e., 20996299801 + 23902321 = 144901^2 + 4889^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21020202097 and 21020202106.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255050529 + ... + 5255050532.

Almost surely, 2^21020202122 is an apocalyptic number.

21020202122 is a deficient number, since it is larger than the sum of its proper divisors (10510101064).

21020202122 is a wasteful number, since it uses less digits than its factorization.

21020202122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10510101063.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21020202122 its reverse (22120202012), we get a palindrome (43140404134).

The spelling of 21020202122 in words is "twenty-one billion, twenty million, two hundred two thousand, one hundred twenty-two".