645543423 has 12 divisors (see below), whose sum is σ = 1065659088. Its totient is φ = 368881920.

The previous prime is 645543421. The next prime is 645543467. The reversal of 645543423 is 324345546.

645543423 is a `hidden beast` number, since 64 + 554 + 3 + 42 + 3 = 666.

It is not a de Polignac number, because 645543423 - 2¹ = 645543421 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645543421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5123298 + ... + 5123423.

It is an arithmetic number, because the mean of its divisors is an integer number (88804924).

Almost surely, 2^645543423 is an apocalyptic number.

645543423 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

645543423 is a deficient number, since it is larger than the sum of its proper divisors (420115665).

645543423 is a wasteful number, since it uses less digits than its factorization.

645543423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10246734 (or 10246731 counting only the distinct ones).

The product of its digits is 172800, while the sum is 36.

The square root of 645543423 is about 25407.5465757715. The cubic root of 645543423 is about 864.2548397894.

Adding to 645543423 its reverse (324345546), we get a palindrome (969888969).

The spelling of 645543423 in words is "six hundred forty-five million, five hundred forty-three thousand, four hundred twenty-three".