121981221 has 20 divisors (see below), whose sum is σ = 188505900. Its totient is φ = 78515136.

The previous prime is 121981169. The next prime is 121981247. The reversal of 121981221 is 122189121.

It can be written as a sum of positive squares in 2 ways, for example, as 97121025 + 24860196 = 9855^2 + 4986^2 .

It is not a de Polignac number, because 121981221 - 2¹⁷ = 121850149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121981271) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 23616 + ... + 28313.

It is an arithmetic number, because the mean of its divisors is an integer number (9425295).

Almost surely, 2^121981221 is an apocalyptic number.

It is an amenable number.

121981221 is a deficient number, since it is larger than the sum of its proper divisors (66524679).

121981221 is an equidigital number, since it uses as much as digits as its factorization.

121981221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51970 (or 51961 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 121981221 is about 11044.5108990847. The cubic root of 121981221 is about 495.9421176060.

The spelling of 121981221 in words is "one hundred twenty-one million, nine hundred eighty-one thousand, two hundred twenty-one".