645316761682 has 8 divisors (see below), whose sum is σ = 967987765116. Its totient is φ = 322654173312.

The previous prime is 645316761679. The next prime is 645316761689. The reversal of 645316761682 is 286167613546.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 540211770081 + 105104991601 = 734991^2 + 324199^2 .

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

It is not an unprimeable number, because it can be changed into a prime (645316761689) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1908423 + ... + 2220970.

Almost surely, 2^645316761682 is an apocalyptic number.

645316761682 is a deficient number, since it is larger than the sum of its proper divisors (322671003434).

645316761682 is a wasteful number, since it uses less digits than its factorization.

645316761682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4207532.

The product of its digits is 8709120, while the sum is 55.

The spelling of 645316761682 in words is "six hundred forty-five billion, three hundred sixteen million, seven hundred sixty-one thousand, six hundred eighty-two".