1645539131376 has 240 divisors, whose sum is σ = 5541501987840. Its totient is φ = 445297927680.

The previous prime is 1645539131359. The next prime is 1645539131387. The reversal of 1645539131376 is 6731319355461.

1645539131376 is a `hidden beast` number, since 1 + 6 + 4 + 5 + 539 + 1 + 31 + 3 + 76 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 102129561 + ... + 102145671.

It is an arithmetic number, because the mean of its divisors is an integer number (23089591616).

Almost surely, 2^{1645539131376} is an apocalyptic number.

1645539131376 is a gapful number since it is divisible by the number (16) 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 1645539131376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2770750993920).

1645539131376 is an abundant number, since it is smaller than the sum of its proper divisors (3895962856464).

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

1645539131376 is a wasteful number, since it uses less digits than its factorization.

1645539131376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21484 (or 21475 counting only the distinct ones).

The product of its digits is 6123600, while the sum is 54.

It can be divided in two parts, 164553 and 9131376, that added together give a palindrome (9295929).

The spelling of 1645539131376 in words is "one trillion, six hundred forty-five billion, five hundred thirty-nine million, one hundred thirty-one thousand, three hundred seventy-six".