1320021 has 6 divisors (see below), whose sum is σ = 1906710. Its totient is φ = 880008.

The previous prime is 1320019. The next prime is 1320023. The reversal of 1320021 is 1200231.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1320019) and next prime (1320023).

It can be written as a sum of positive squares in only one way, i.e., 1179396 + 140625 = 1086^2 + 375^2 .

It is not a de Polignac number, because 1320021 - 2¹ = 1320019 is a prime.

It is a super-3 number, since 3×1320021³ = 6900233318839107783, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 146669 = 1320021 / (1 + 3 + 2 + 0 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 1319985 and 1320012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1320023) 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, 73326 + ... + 73343.

It is an arithmetic number, because the mean of its divisors is an integer number (317785).

2^1320021 is an apocalyptic number.

It is an amenable number.

1320021 is a deficient number, since it is larger than the sum of its proper divisors (586689).

1320021 is a wasteful number, since it uses less digits than its factorization.

1320021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146675 (or 146672 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 1320021 is about 1148.9216683482. The cubic root of 1320021 is about 109.6967127675.

Adding to 1320021 its reverse (1200231), we get a palindrome (2520252).

The spelling of 1320021 in words is "one million, three hundred twenty thousand, twenty-one".