1220121021 has 24 divisors (see below), whose sum is σ = 1893749760. Its totient is φ = 696726912.

The previous prime is 1220121017. The next prime is 1220121037. The reversal of 1220121021 is 1201210221.

It is not a de Polignac number, because 1220121021 - 2² = 1220121017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1220120988 and 1220121006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220121061) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 393445 + ... + 396533.

It is an arithmetic number, because the mean of its divisors is an integer number (78906240).

Almost surely, 2^1220121021 is an apocalyptic number.

It is an amenable number.

1220121021 is a deficient number, since it is larger than the sum of its proper divisors (673628739).

1220121021 is a wasteful number, since it uses less digits than its factorization.

1220121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5793 (or 5786 counting only the distinct ones).

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

The square root of 1220121021 is about 34930.2307607608. The cubic root of 1220121021 is about 1068.5650608212.

Adding to 1220121021 its reverse (1201210221), we get a palindrome (2421331242).

It can be divided in two parts, 1 and 220121021, that added together give a palindrome (220121022).

The spelling of 1220121021 in words is "one billion, two hundred twenty million, one hundred twenty-one thousand, twenty-one".