645344303420400 has 240 divisors, whose sum is σ = 2157169650282240. Its totient is φ = 164606801356800.

The previous prime is 645344303420389. The next prime is 645344303420417. The reversal of 645344303420400 is 4024303443546.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×645344303420400² (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 (31) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2024825055 + ... + 2025143745.

It is an arithmetic number, because the mean of its divisors is an integer number (8988206876176).

Almost surely, 2^{645344303420400} is an apocalyptic number.

645344303420400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645344303420400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1078584825141120).

645344303420400 is an abundant number, since it is smaller than the sum of its proper divisors (1511825346861840).

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

645344303420400 is a wasteful number, since it uses less digits than its factorization.

645344303420400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392104 (or 392093 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 42.

Adding to 645344303420400 its reverse (4024303443546), we get a palindrome (649368606863946).

The spelling of 645344303420400 in words is "six hundred forty-five trillion, three hundred forty-four billion, three hundred three million, four hundred twenty thousand, four hundred".