1220205121 has 4 divisors (see below), whose sum is σ = 1222091712. Its totient is φ = 1218318532.

The previous prime is 1220205113. The next prime is 1220205149. The reversal of 1220205121 is 1215020221.

It is a happy number.

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: 1215020221 = 29 ⋅41897249.

It is a cyclic number.

It is not a de Polignac number, because 1220205121 - 2³ = 1220205113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220205095 and 1220205104.

It is not an unprimeable number, because it can be changed into a prime (1227205121) 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, 942325 + ... + 943618.

It is an arithmetic number, because the mean of its divisors is an integer number (305522928).

Almost surely, 2^1220205121 is an apocalyptic number.

It is an amenable number.

1220205121 is a deficient number, since it is larger than the sum of its proper divisors (1886591).

1220205121 is an equidigital number, since it uses as much as digits as its factorization.

1220205121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1886590.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 1220205121 is about 34931.4345683082. The cubic root of 1220205121 is about 1068.5896114615.

Adding to 1220205121 its reverse (1215020221), we get a palindrome (2435225342).

The spelling of 1220205121 in words is "one billion, two hundred twenty million, two hundred five thousand, one hundred twenty-one".