645644145125 has 36 divisors (see below), whose sum is σ = 937408484844. Its totient is φ = 442684292400.

The previous prime is 645644145121. The next prime is 645644145131. The reversal of 645644145125 is 521541446546.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 20660612644 + 624983532481 = 143738^2 + 790559^2 .

It is not a de Polignac number, because 645644145125 - 2² = 645644145121 is a prime.

It is a super-2 number, since 2×645644145125² (a number of 24 digits) contains 22 as substring.

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 645644145125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645644145121) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 62880242 + ... + 62890508.

It is an arithmetic number, because the mean of its divisors is an integer number (26039124579).

Almost surely, 2^645644145125 is an apocalyptic number.

It is an amenable number.

645644145125 is a deficient number, since it is larger than the sum of its proper divisors (291764339719).

645644145125 is an frugal number, since it uses more digits than its factorization.

645644145125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20563 (or 10279 counting only the distinct ones).

The product of its digits is 2304000, while the sum is 47.

The spelling of 645644145125 in words is "six hundred forty-five billion, six hundred forty-four million, one hundred forty-five thousand, one hundred twenty-five".