645389513 has 4 divisors (see below), whose sum is σ = 683353620. Its totient is φ = 607425408.

The previous prime is 645389509. The next prime is 645389539. The reversal of 645389513 is 315983546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 253032649 + 392356864 = 15907^2 + 19808^2 .

It is a cyclic number.

It is not a de Polignac number, because 645389513 - 2² = 645389509 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645389543) 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, 18982028 + ... + 18982061.

It is an arithmetic number, because the mean of its divisors is an integer number (170838405).

Almost surely, 2^645389513 is an apocalyptic number.

It is an amenable number.

645389513 is a deficient number, since it is larger than the sum of its proper divisors (37964107).

645389513 is a wasteful number, since it uses less digits than its factorization.

645389513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37964106.

The product of its digits is 388800, while the sum is 44.

The square root of 645389513 is about 25404.5175706999. The cubic root of 645389513 is about 864.1861493237.

The spelling of 645389513 in words is "six hundred forty-five million, three hundred eighty-nine thousand, five hundred thirteen".