21221201212099 has 4 divisors (see below), whose sum is σ = 24252801385264. Its totient is φ = 18189601038936.

The previous prime is 21221201212061. The next prime is 21221201212109. The reversal of 21221201212099 is 99021210212212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21221201212099 - 2¹¹ = 21221201210051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221201212399) 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, 1515800086572 + ... + 1515800086585.

It is an arithmetic number, because the mean of its divisors is an integer number (6063200346316).

Almost surely, 2^{21221201212099} is an apocalyptic number.

21221201212099 is a deficient number, since it is larger than the sum of its proper divisors (3031600173165).

21221201212099 is an equidigital number, since it uses as much as digits as its factorization.

21221201212099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3031600173164.

The product of its (nonzero) digits is 5184, while the sum is 34.

The spelling of 21221201212099 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, ninety-nine".