645218123 has 8 divisors (see below), whose sum is σ = 708939840. Its totient is φ = 582340680.

The previous prime is 645218117. The next prime is 645218137. The reversal of 645218123 is 321812546.

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 645218123 - 2¹⁶ = 645152587 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645218123.

It is not an unprimeable number, because it can be changed into a prime (645218423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209465 + ... + 212522.

It is an arithmetic number, because the mean of its divisors is an integer number (88617480).

Almost surely, 2^645218123 is an apocalyptic number.

645218123 is a deficient number, since it is larger than the sum of its proper divisors (63721717).

645218123 is a wasteful number, since it uses less digits than its factorization.

645218123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422137.

The product of its digits is 11520, while the sum is 32.

The square root of 645218123 is about 25401.1441277750. The cubic root of 645218123 is about 864.1096446321.

The spelling of 645218123 in words is "six hundred forty-five million, two hundred eighteen thousand, one hundred twenty-three".