645555200681 has 8 divisors (see below), whose sum is σ = 645857906400. Its totient is φ = 645252564640.

The previous prime is 645555200651. The next prime is 645555200699. The reversal of 645555200681 is 186002555546.

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

It is a cyclic number.

It is not a de Polignac number, because 645555200681 - 2¹⁸ = 645554938537 is a prime.

It is a super-2 number, since 2×645555200681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645555200621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28288766 + ... + 28311576.

It is an arithmetic number, because the mean of its divisors is an integer number (80732238300).

Almost surely, 2^645555200681 is an apocalyptic number.

It is an amenable number.

645555200681 is a deficient number, since it is larger than the sum of its proper divisors (302705719).

645555200681 is a wasteful number, since it uses less digits than its factorization.

645555200681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34839.

The product of its (nonzero) digits is 1440000, while the sum is 47.

The spelling of 645555200681 in words is "six hundred forty-five billion, five hundred fifty-five million, two hundred thousand, six hundred eighty-one".