1645337193680 has 90 divisors (see below), whose sum is σ = 3890803613814. Its totient is φ = 647070432000.

The previous prime is 1645337193659. The next prime is 1645337193727. The reversal of 1645337193680 is 863917335461.

It can be written as a sum of positive squares in 3 ways, for example, as 127700451904 + 1517636741776 = 357352^2 + 1231924^2 .

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 17 ways as a sum of consecutive naturals, for example, 699844505 + ... + 699846855.

Almost surely, 2^{1645337193680} is an apocalyptic number.

1645337193680 is a gapful number since it is divisible by the number (10) 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 1645337193680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1945401806907).

1645337193680 is an abundant number, since it is smaller than the sum of its proper divisors (2245466420134).

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

1645337193680 is an frugal number, since it uses more digits than its factorization.

1645337193680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4837 (or 2419 counting only the distinct ones).

The product of its (nonzero) digits is 9797760, while the sum is 56.

The spelling of 1645337193680 in words is "one trillion, six hundred forty-five billion, three hundred thirty-seven million, one hundred ninety-three thousand, six hundred eighty".