645213013 has 4 divisors (see below), whose sum is σ = 666026368. Its totient is φ = 624399660.

The previous prime is 645213007. The next prime is 645213031. The reversal of 645213013 is 310312546.

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: 310312546 = 2 ⋅155156273.

It is a cyclic number.

It is not a de Polignac number, because 645213013 - 2⁹ = 645212501 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 (645213113) 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, 10406631 + ... + 10406692.

It is an arithmetic number, because the mean of its divisors is an integer number (166506592).

Almost surely, 2^645213013 is an apocalyptic number.

It is an amenable number.

645213013 is a deficient number, since it is larger than the sum of its proper divisors (20813355).

645213013 is a wasteful number, since it uses less digits than its factorization.

645213013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20813354.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 645213013 is about 25401.0435415555. The cubic root of 645213013 is about 864.1073634335.

Adding to 645213013 its reverse (310312546), we get a palindrome (955525559).

The spelling of 645213013 in words is "six hundred forty-five million, two hundred thirteen thousand, thirteen".