21221111021210 has 8 divisors (see below), whose sum is σ = 38197999838196. Its totient is φ = 8488444408480.

The previous prime is 21221111021191. The next prime is 21221111021213. The reversal of 21221111021210 is 1212011112212.

It can be written as a sum of positive squares in 2 ways, for example, as 20401906821409 + 819204199801 = 4516847^2 + 905099^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21221111021213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1061055551051 + ... + 1061055551070.

Almost surely, 2^{21221111021210} is an apocalyptic number.

21221111021210 is a deficient number, since it is larger than the sum of its proper divisors (16976888816986).

21221111021210 is a wasteful number, since it uses less digits than its factorization.

21221111021210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2122111102128.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21221111021210 its reverse (1212011112212), we get a palindrome (22433122133422).

The spelling of 21221111021210 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, twenty-one thousand, two hundred ten".