1320220021 has 2 divisors, whose sum is σ = 1320220022. Its totient is φ = 1320220020.

The previous prime is 1320220009. The next prime is 1320220039. The reversal of 1320220021 is 1200220231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680635921 + 639584100 = 26089^2 + 25290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1320220021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1320219983 and 1320220010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1320220001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660110010 + 660110011.

It is an arithmetic number, because the mean of its divisors is an integer number (660110011).

Almost surely, 2^1320220021 is an apocalyptic number.

It is an amenable number.

1320220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320220021 is an equidigital number, since it uses as much as digits as its factorization.

1320220021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 1320220021 is about 36334.8320623613. The cubic root of 1320220021 is about 1097.0222552128.

Adding to 1320220021 its reverse (1200220231), we get a palindrome (2520440252).

The spelling of 1320220021 in words is "one billion, three hundred twenty million, two hundred twenty thousand, twenty-one".