21221100202 has 4 divisors (see below), whose sum is σ = 31831650306. Its totient is φ = 10610550100.

The previous prime is 21221100163. The next prime is 21221100223. The reversal of 21221100202 is 20200112212.

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., 19759643761 + 1461456441 = 140569^2 + 38229^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5305275049 + ... + 5305275052.

Almost surely, 2^21221100202 is an apocalyptic number.

21221100202 is a deficient number, since it is larger than the sum of its proper divisors (10610550104).

21221100202 is a wasteful number, since it uses less digits than its factorization.

21221100202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10610550103.

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

Adding to 21221100202 its reverse (20200112212), we get a palindrome (41421212414).

The spelling of 21221100202 in words is "twenty-one billion, two hundred twenty-one million, one hundred thousand, two hundred two".