1645644349440 has 1824 divisors, whose sum is σ = 7430447021760. Its totient is φ = 342456532992.

The previous prime is 1645644349439. The next prime is 1645644349471. The reversal of 1645644349440 is 449434465461.

1645644349440 is a `hidden beast` number, since 1 + 6 + 4 + 564 + 4 + 34 + 9 + 4 + 40 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 22543073244 + ... + 22543073316.

It is an arithmetic number, because the mean of its divisors is an integer number (4073709990).

Almost surely, 2^{1645644349440} is an apocalyptic number.

1645644349440 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 1645644349440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3715223510880).

1645644349440 is an abundant number, since it is smaller than the sum of its proper divisors (5784802672320).

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

1645644349440 is an frugal number, since it uses more digits than its factorization.

1645644349440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 19906560, while the sum is 54.

The spelling of 1645644349440 in words is "one trillion, six hundred forty-five billion, six hundred forty-four million, three hundred forty-nine thousand, four hundred forty".