1320005021 has 4 divisors (see below), whose sum is σ = 1329501600. Its totient is φ = 1310508444.

The previous prime is 1320004999. The next prime is 1320005033. The reversal of 1320005021 is 1205000231.

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: 1205000231 = 1259 ⋅957109.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1320005021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1320004987 and 1320005005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1320005321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4748081 + ... + 4748358.

It is an arithmetic number, because the mean of its divisors is an integer number (332375400).

Almost surely, 2^1320005021 is an apocalyptic number.

It is an amenable number.

1320005021 is a deficient number, since it is larger than the sum of its proper divisors (9496579).

1320005021 is an equidigital number, since it uses as much as digits as its factorization.

1320005021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9496578.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 1320005021 is about 36331.8733483425. The cubic root of 1320005021 is about 1096.9627013541.

Adding to 1320005021 its reverse (1205000231), we get a palindrome (2525005252).

The spelling of 1320005021 in words is "one billion, three hundred twenty million, five thousand, twenty-one".