21212221202 has 4 divisors (see below), whose sum is σ = 31818331806. Its totient is φ = 10606110600.

The previous prime is 21212221193. The next prime is 21212221237. The reversal of 21212221202 is 20212221212.

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., 14251823161 + 6960398041 = 119381^2 + 83429^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5303055299 + ... + 5303055302.

Almost surely, 2^21212221202 is an apocalyptic number.

21212221202 is a deficient number, since it is larger than the sum of its proper divisors (10606110604).

21212221202 is a wasteful number, since it uses less digits than its factorization.

21212221202 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10606110603.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21212221202 its reverse (20212221212), we get a palindrome (41424442414).

The spelling of 21212221202 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, two hundred two".