1645232213 has 4 divisors (see below), whose sum is σ = 1652480160. Its totient is φ = 1637984268.

The previous prime is 1645232207. The next prime is 1645232221. The reversal of 1645232213 is 3122325461.

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.

It is a cyclic number.

It is not a de Polignac number, because 1645232213 - 2¹⁸ = 1644970069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645232203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3623633 + ... + 3624086.

It is an arithmetic number, because the mean of its divisors is an integer number (413120040).

Almost surely, 2^1645232213 is an apocalyptic number.

It is an amenable number.

1645232213 is a deficient number, since it is larger than the sum of its proper divisors (7247947).

1645232213 is an equidigital number, since it uses as much as digits as its factorization.

1645232213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7247946.

The product of its digits is 8640, while the sum is 29.

The square root of 1645232213 is about 40561.4621654595. The cubic root of 1645232213 is about 1180.5264846345.

Adding to 1645232213 its reverse (3122325461), we get a palindrome (4767557674).

The spelling of 1645232213 in words is "one billion, six hundred forty-five million, two hundred thirty-two thousand, two hundred thirteen".