1645206764544 has 792 divisors, whose sum is σ = 5830440295680. Its totient is φ = 461889921024.

The previous prime is 1645206764521. The next prime is 1645206764573. The reversal of 1645206764544 is 4454676025461.

1645206764544 is a `hidden beast` number, since 1 + 6 + 4 + 5 + 20 + 6 + 76 + 4 + 544 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 71 ways as a sum of consecutive naturals, for example, 719372169 + ... + 719374455.

It is an arithmetic number, because the mean of its divisors is an integer number (7361667040).

Almost surely, 2^{1645206764544} is an apocalyptic number.

1645206764544 is a gapful number since it is divisible by the number (14) 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 1645206764544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2915220147840).

1645206764544 is an abundant number, since it is smaller than the sum of its proper divisors (4185233531136).

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

1645206764544 is an equidigital number, since it uses as much as digits as its factorization.

1645206764544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2395 (or 2358 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 54.

The spelling of 1645206764544 in words is "one trillion, six hundred forty-five billion, two hundred six million, seven hundred sixty-four thousand, five hundred forty-four".