645405123 has 16 divisors (see below), whose sum is σ = 951996672. Its totient is φ = 385644000.

The previous prime is 645405113. The next prime is 645405157. The reversal of 645405123 is 321504546.

It is not a de Polignac number, because 645405123 - 2²⁵ = 611850691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645405113) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135388 + ... + 140073.

It is an arithmetic number, because the mean of its divisors is an integer number (59499792).

Almost surely, 2^645405123 is an apocalyptic number.

645405123 is a deficient number, since it is larger than the sum of its proper divisors (306591549).

645405123 is a wasteful number, since it uses less digits than its factorization.

645405123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275546.

The product of its (nonzero) digits is 14400, while the sum is 30.

The square root of 645405123 is about 25404.8247976639. The cubic root of 645405123 is about 864.1931166082.

Adding to 645405123 its reverse (321504546), we get a palindrome (966909669).

The spelling of 645405123 in words is "six hundred forty-five million, four hundred five thousand, one hundred twenty-three".