645323621153 has 4 divisors (see below), whose sum is σ = 683283834180. Its totient is φ = 607363408128.

The previous prime is 645323621077. The next prime is 645323621167. The reversal of 645323621153 is 351126323546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 519598772224 + 125724848929 = 720832^2 + 354577^2 .

It is a cyclic number.

It is not a de Polignac number, because 645323621153 - 2²⁰ = 645322572577 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 645323621153.

It is not an unprimeable number, because it can be changed into a prime (645323620153) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18980106488 + ... + 18980106521.

It is an arithmetic number, because the mean of its divisors is an integer number (170820958545).

Almost surely, 2^645323621153 is an apocalyptic number.

It is an amenable number.

645323621153 is a deficient number, since it is larger than the sum of its proper divisors (37960213027).

645323621153 is a wasteful number, since it uses less digits than its factorization.

645323621153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37960213026.

The product of its digits is 388800, while the sum is 41.

Adding to 645323621153 its reverse (351126323546), we get a palindrome (996449944699).

The spelling of 645323621153 in words is "six hundred forty-five billion, three hundred twenty-three million, six hundred twenty-one thousand, one hundred fifty-three".