83121221 has 6 divisors (see below), whose sum is σ = 86038290. Its totient is φ = 80207568.

The previous prime is 83121217. The next prime is 83121251. The reversal of 83121221 is 12212138.

It can be written as a sum of positive squares in 3 ways, for example, as 6558721 + 76562500 = 2561^2 + 8750^2 .

It is not a de Polignac number, because 83121221 - 2² = 83121217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 83121193 and 83121202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83121251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 48251 + ... + 49943.

It is an arithmetic number, because the mean of its divisors is an integer number (14339715).

Almost surely, 2^83121221 is an apocalyptic number.

It is an amenable number.

83121221 is a deficient number, since it is larger than the sum of its proper divisors (2917069).

83121221 is an frugal number, since it uses more digits than its factorization.

83121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3415 (or 1722 counting only the distinct ones).

The product of its digits is 192, while the sum is 20.

The square root of 83121221 is about 9117.0840184787. The cubic root of 83121221 is about 436.4193231107.

Adding to 83121221 its reverse (12212138), we get a palindrome (95333359).

The spelling of 83121221 in words is "eighty-three million, one hundred twenty-one thousand, two hundred twenty-one".