1321445645 has 24 divisors (see below), whose sum is σ = 1724848200. Its totient is φ = 971433216.

The previous prime is 1321445641. The next prime is 1321445651. The reversal of 1321445645 is 5465441231.

It can be written as a sum of positive squares in 12 ways, for example, as 388326436 + 933119209 = 19706^2 + 30547^2 .

It is not a de Polignac number, because 1321445645 - 2² = 1321445641 is a prime.

It is a super-3 number, since 3×1321445645³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321445641) 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, 190091 + ... + 196919.

It is an arithmetic number, because the mean of its divisors is an integer number (71868675).

Almost surely, 2^1321445645 is an apocalyptic number.

It is an amenable number.

1321445645 is a deficient number, since it is larger than the sum of its proper divisors (403402555).

1321445645 is a wasteful number, since it uses less digits than its factorization.

1321445645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7089 (or 7076 counting only the distinct ones).

The product of its digits is 57600, while the sum is 35.

The square root of 1321445645 is about 36351.6938394898. The cubic root of 1321445645 is about 1097.3616231291.

Adding to 1321445645 its reverse (5465441231), we get a palindrome (6786886876).

The spelling of 1321445645 in words is "one billion, three hundred twenty-one million, four hundred forty-five thousand, six hundred forty-five".