1216220101 has 4 divisors (see below), whose sum is σ = 1227586752. Its totient is φ = 1204853452.

The previous prime is 1216220063. The next prime is 1216220119. The reversal of 1216220101 is 1010226121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1010226121 = 1423 ⋅709927.

It is a cyclic number.

It is not a de Polignac number, because 1216220101 - 2⁷ = 1216219973 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 (1216220701) 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, 5683165 + ... + 5683378.

It is an arithmetic number, because the mean of its divisors is an integer number (306896688).

Almost surely, 2^1216220101 is an apocalyptic number.

It is an amenable number.

1216220101 is a deficient number, since it is larger than the sum of its proper divisors (11366651).

1216220101 is a wasteful number, since it uses less digits than its factorization.

1216220101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11366650.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 1216220101 is about 34874.3473200575. The cubic root of 1216220101 is about 1067.4250544931.

Adding to 1216220101 its reverse (1010226121), we get a palindrome (2226446222).

The spelling of 1216220101 in words is "one billion, two hundred sixteen million, two hundred twenty thousand, one hundred one".