645123504505 has 8 divisors (see below), whose sum is σ = 774165147912. Its totient is φ = 516087508608.

The previous prime is 645123504479. The next prime is 645123504539. The reversal of 645123504505 is 505405321546.

It can be written as a sum of positive squares in 4 ways, for example, as 278120171641 + 367003332864 = 527371^2 + 605808^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645123504505 - 2¹⁵ = 645123471737 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1156362 + ... + 1620931.

It is an arithmetic number, because the mean of its divisors is an integer number (96770643489).

Almost surely, 2^645123504505 is an apocalyptic number.

It is an amenable number.

645123504505 is a deficient number, since it is larger than the sum of its proper divisors (129041643407).

645123504505 is a wasteful number, since it uses less digits than its factorization.

645123504505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2823755.

The product of its (nonzero) digits is 360000, while the sum is 40.

The spelling of 645123504505 in words is "six hundred forty-five billion, one hundred twenty-three million, five hundred four thousand, five hundred five".