645891831855 has 12 divisors (see below), whose sum is σ = 1119545841960. Its totient is φ = 344475643632.

The previous prime is 645891831821. The next prime is 645891831877. The reversal of 645891831855 is 558138198546.

645891831855 is a `hidden beast` number, since 6 + 4 + 589 + 18 + 31 + 8 + 5 + 5 = 666.

It is not a de Polignac number, because 645891831855 - 2¹³ = 645891823663 is a prime.

It is a super-3 number, since 3×645891831855³ (a number of 36 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645891831792 and 645891831801.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7176575865 + ... + 7176575954.

It is an arithmetic number, because the mean of its divisors is an integer number (93295486830).

Almost surely, 2^645891831855 is an apocalyptic number.

645891831855 is a deficient number, since it is larger than the sum of its proper divisors (473654010105).

645891831855 is a wasteful number, since it uses less digits than its factorization.

645891831855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14353151830 (or 14353151827 counting only the distinct ones).

The product of its digits is 41472000, while the sum is 63.

The spelling of 645891831855 in words is "six hundred forty-five billion, eight hundred ninety-one million, eight hundred thirty-one thousand, eight hundred fifty-five".