1641805440 has 384 divisors, whose sum is σ = 5938652160. Its totient is φ = 385228800.

The previous prime is 1641805411. The next prime is 1641805483. The reversal of 1641805440 is 445081461.

1641805440 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-3 number, since 3×1641805440³ (a number of 29 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 8595745 + ... + 8595935.

It is an arithmetic number, because the mean of its divisors is an integer number (15465240).

Almost surely, 2^1641805440 is an apocalyptic number.

1641805440 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 1641805440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2969326080).

1641805440 is an abundant number, since it is smaller than the sum of its proper divisors (4296846720).

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

1641805440 is a wasteful number, since it uses less digits than its factorization.

1641805440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 1641805440 is about 40519.1984126044. The cubic root of 1641805440 is about 1179.7062948040.

The spelling of 1641805440 in words is "one billion, six hundred forty-one million, eight hundred five thousand, four hundred forty".