645343705523 has 4 divisors (see below), whose sum is σ = 704011315128. Its totient is φ = 586676095920.

The previous prime is 645343705499. The next prime is 645343705571. The reversal of 645343705523 is 325507343546.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645343705523 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645343705723) 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, 29333804786 + ... + 29333804807.

It is an arithmetic number, because the mean of its divisors is an integer number (176002828782).

Almost surely, 2^645343705523 is an apocalyptic number.

645343705523 is a deficient number, since it is larger than the sum of its proper divisors (58667609605).

645343705523 is a wasteful number, since it uses less digits than its factorization.

645343705523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58667609604.

The product of its (nonzero) digits is 4536000, while the sum is 47.

The spelling of 645343705523 in words is "six hundred forty-five billion, three hundred forty-three million, seven hundred five thousand, five hundred twenty-three".