645531685386 has 32 divisors (see below), whose sum is σ = 1482001021440. Its totient is φ = 183625121136.

The previous prime is 645531685289. The next prime is 645531685387. The reversal of 645531685386 is 683586135546.

It is a super-2 number, since 2×645531685386² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645531685387) 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 15 ways as a sum of consecutive naturals, for example, 33844656 + ... + 33863723.

It is an arithmetic number, because the mean of its divisors is an integer number (46312531920).

Almost surely, 2^645531685386 is an apocalyptic number.

645531685386 is an abundant number, since it is smaller than the sum of its proper divisors (836469336054).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645531685386 is a wasteful number, since it uses less digits than its factorization.

645531685386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67708618.

The product of its digits is 62208000, while the sum is 60.

The spelling of 645531685386 in words is "six hundred forty-five billion, five hundred thirty-one million, six hundred eighty-five thousand, three hundred eighty-six".