645446664001020 has 288 divisors, whose sum is σ = 2178238631865408. Its totient is φ = 142273052909568.

The previous prime is 645446664001003. The next prime is 645446664001079. The reversal of 645446664001020 is 20100466644546.

It is a super-2 number, since 2×645446664001020² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 13962307 + ... + 38546586.

It is an arithmetic number, because the mean of its divisors is an integer number (7563328582866).

Almost surely, 2^{645446664001020} is an apocalyptic number.

645446664001020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645446664001020 is an abundant number, since it is smaller than the sum of its proper divisors (1532791967864388).

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

645446664001020 is a wasteful number, since it uses less digits than its factorization.

645446664001020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52509069 (or 52509060 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 48.

It can be divided in two parts, 645446 and 664001020, that added together give a palindrome (664646466).

The spelling of 645446664001020 in words is "six hundred forty-five trillion, four hundred forty-six billion, six hundred sixty-four million, one thousand, twenty".