645491000109 has 4 divisors (see below), whose sum is σ = 860654666816. Its totient is φ = 430327333404.

The previous prime is 645491000107. The next prime is 645491000117. The reversal of 645491000109 is 901000194546.

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 not a de Polignac number, because 645491000109 - 2¹ = 645491000107 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 (645491000107) 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, 107581833349 + ... + 107581833354.

It is an arithmetic number, because the mean of its divisors is an integer number (215163666704).

Almost surely, 2^645491000109 is an apocalyptic number.

It is an amenable number.

645491000109 is a deficient number, since it is larger than the sum of its proper divisors (215163666707).

645491000109 is a wasteful number, since it uses less digits than its factorization.

645491000109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215163666706.

The product of its (nonzero) digits is 38880, while the sum is 39.

The spelling of 645491000109 in words is "six hundred forty-five billion, four hundred ninety-one million, one hundred nine", and thus it is an aban number.