1321645 has 8 divisors (see below), whose sum is σ = 1708056. Its totient is φ = 975936.

The previous prime is 1321637. The next prime is 1321651. The reversal of 1321645 is 5461231.

It can be written as a sum of positive squares in 4 ways, for example, as 227529 + 1094116 = 477^2 + 1046^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1321645 - 2³ = 1321637 is a prime.

It is a super-3 number, since 3×1321645³ = 6925732392931233375, which contains 333 as substring.

It is a Duffinian number.

1321645 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10102 + ... + 10231.

It is an arithmetic number, because the mean of its divisors is an integer number (213507).

2^1321645 is an apocalyptic number.

It is an amenable number.

1321645 is a deficient number, since it is larger than the sum of its proper divisors (386411).

1321645 is a wasteful number, since it uses less digits than its factorization.

1321645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20351.

The product of its digits is 720, while the sum is 22.

The square root of 1321645 is about 1149.6282007675. The cubic root of 1321645 is about 109.7416803486.

Adding to 1321645 its reverse (5461231), we get a palindrome (6782876).

The spelling of 1321645 in words is "one million, three hundred twenty-one thousand, six hundred forty-five".