1221012101 has 4 divisors (see below), whose sum is σ = 1221153900. Its totient is φ = 1220870304.

The previous prime is 1221012083. The next prime is 1221012119. The reversal of 1221012101 is 1012101221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1012101221 = 7109 ⋅142369.

It is an interprime number because it is at equal distance from previous prime (1221012083) and next prime (1221012119).

It can be written as a sum of positive squares in 2 ways, for example, as 429940225 + 791071876 = 20735^2 + 28126^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221012101 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 (1221012601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57086 + ... + 75503.

It is an arithmetic number, because the mean of its divisors is an integer number (305288475).

Almost surely, 2^1221012101 is an apocalyptic number.

It is an amenable number.

1221012101 is a deficient number, since it is larger than the sum of its proper divisors (141799).

1221012101 is an equidigital number, since it uses as much as digits as its factorization.

1221012101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141798.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 1221012101 is about 34942.9835732440. The cubic root of 1221012101 is about 1068.8251293537.

Adding to 1221012101 its reverse (1012101221), we get a palindrome (2233113322).

The spelling of 1221012101 in words is "one billion, two hundred twenty-one million, twelve thousand, one hundred one".