645623605645 has 8 divisors (see below), whose sum is σ = 789366220056. Its totient is φ = 506753622336.

The previous prime is 645623605639. The next prime is 645623605699. The reversal of 645623605645 is 546506326546.

It can be written as a sum of positive squares in 4 ways, for example, as 280123557289 + 365500048356 = 529267^2 + 604566^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645623605645 is a prime.

It is a super-3 number, since 3×645623605645³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645623605592 and 645623605601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1218157482 + ... + 1218158011.

It is an arithmetic number, because the mean of its divisors is an integer number (98670777507).

Almost surely, 2^645623605645 is an apocalyptic number.

It is an amenable number.

645623605645 is a deficient number, since it is larger than the sum of its proper divisors (143742614411).

645623605645 is a wasteful number, since it uses less digits than its factorization.

645623605645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2436315551.

The product of its (nonzero) digits is 15552000, while the sum is 52.

The spelling of 645623605645 in words is "six hundred forty-five billion, six hundred twenty-three million, six hundred five thousand, six hundred forty-five".