642655345 has 4 divisors (see below), whose sum is σ = 771186420. Its totient is φ = 514124272.

The previous prime is 642655337. The next prime is 642655417. The reversal of 642655345 is 543556246.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 543556246 = 2 ⋅271778123.

It can be written as a sum of positive squares in 2 ways, for example, as 288048784 + 354606561 = 16972^2 + 18831^2 .

It is a cyclic number.

It is not a de Polignac number, because 642655345 - 2³ = 642655337 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 642655298 and 642655307.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64265530 + ... + 64265539.

It is an arithmetic number, because the mean of its divisors is an integer number (192796605).

Almost surely, 2^642655345 is an apocalyptic number.

It is an amenable number.

642655345 is a deficient number, since it is larger than the sum of its proper divisors (128531075).

642655345 is a wasteful number, since it uses less digits than its factorization.

642655345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128531074.

The product of its digits is 432000, while the sum is 40.

The square root of 642655345 is about 25350.6478220972. The cubic root of 642655345 is about 862.9640580527.

Subtracting from 642655345 its reverse (543556246), we obtain a palindrome (99099099).

The spelling of 642655345 in words is "six hundred forty-two million, six hundred fifty-five thousand, three hundred forty-five".