1221100012109 has 4 divisors (see below), whose sum is σ = 1292929424604. Its totient is φ = 1149270599616.

The previous prime is 1221100012103. The next prime is 1221100012127. The reversal of 1221100012109 is 9012100011221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 717276874084 + 503823138025 = 846922^2 + 709805^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221100012109 - 2¹² = 1221100008013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221100012103) 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, 35914706222 + ... + 35914706255.

It is an arithmetic number, because the mean of its divisors is an integer number (323232356151).

Almost surely, 2^{1221100012109} is an apocalyptic number.

It is an amenable number.

1221100012109 is a deficient number, since it is larger than the sum of its proper divisors (71829412495).

1221100012109 is an equidigital number, since it uses as much as digits as its factorization.

1221100012109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71829412494.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 1221100012109 in words is "one trillion, two hundred twenty-one billion, one hundred million, twelve thousand, one hundred nine".