21021221221202 has 4 divisors (see below), whose sum is σ = 31531831831806. Its totient is φ = 10510610610600.

The previous prime is 21021221221199. The next prime is 21021221221241. The reversal of 21021221221202 is 20212212212012.

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., 12826633682041 + 8194587539161 = 3581429^2 + 2862619^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255305305299 + ... + 5255305305302.

Almost surely, 2^{21021221221202} is an apocalyptic number.

21021221221202 is a deficient number, since it is larger than the sum of its proper divisors (10510610610604).

21021221221202 is a wasteful number, since it uses less digits than its factorization.

21021221221202 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10510610610603.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21021221221202 its reverse (20212212212012), we get a palindrome (41233433433214).

The spelling of 21021221221202 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, two hundred two".