1221202101 has 16 divisors (see below), whose sum is σ = 1877955200. Its totient is φ = 691426368.

The previous prime is 1221202091. The next prime is 1221202133. The reversal of 1221202101 is 1012021221.

It is not a de Polignac number, because 1221202101 - 2²³ = 1212813493 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 (1221202601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 264466 + ... + 269043.

It is an arithmetic number, because the mean of its divisors is an integer number (117372200).

Almost surely, 2^1221202101 is an apocalyptic number.

It is an amenable number.

1221202101 is a deficient number, since it is larger than the sum of its proper divisors (656753099).

1221202101 is a wasteful number, since it uses less digits than its factorization.

1221202101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533628.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221202101 is about 34945.7021820996. The cubic root of 1221202101 is about 1068.8805659438.

Adding to 1221202101 its reverse (1012021221), we get a palindrome (2233223322).

The spelling of 1221202101 in words is "one billion, two hundred twenty-one million, two hundred two thousand, one hundred one".