21212100202 has 4 divisors (see below), whose sum is σ = 31818150306. Its totient is φ = 10606050100.

The previous prime is 21212100193. The next prime is 21212100229. The reversal of 21212100202 is 20200121212.

It is a happy number.

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., 10683082881 + 10529017321 = 103359^2 + 102611^2 .

It is a super-3 number, since 3×21212100202³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5303025049 + ... + 5303025052.

Almost surely, 2^21212100202 is an apocalyptic number.

21212100202 is a deficient number, since it is larger than the sum of its proper divisors (10606050104).

21212100202 is a wasteful number, since it uses less digits than its factorization.

21212100202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10606050103.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21212100202 its reverse (20200121212), we get a palindrome (41412221414).

The spelling of 21212100202 in words is "twenty-one billion, two hundred twelve million, one hundred thousand, two hundred two".