1216221101 has 2 divisors, whose sum is σ = 1216221102. Its totient is φ = 1216221100.

The previous prime is 1216221031. The next prime is 1216221107. The reversal of 1216221101 is 1011226121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1103967076 + 112254025 = 33226^2 + 10595^2 .

It is an emirp because it is prime and its reverse (1011226121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216221101 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1216221101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216221107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608110550 + 608110551.

It is an arithmetic number, because the mean of its divisors is an integer number (608110551).

Almost surely, 2^1216221101 is an apocalyptic number.

It is an amenable number.

1216221101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216221101 is an equidigital number, since it uses as much as digits as its factorization.

1216221101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 1216221101 is about 34874.3616572404. The cubic root of 1216221101 is about 1067.4253470456.

Adding to 1216221101 its reverse (1011226121), we get a palindrome (2227447222).

The spelling of 1216221101 in words is "one billion, two hundred sixteen million, two hundred twenty-one thousand, one hundred one".