1644400560 has 80 divisors (see below), whose sum is σ = 5561072640. Its totient is φ = 398641920.

The previous prime is 1644400559. The next prime is 1644400591. The reversal of 1644400560 is 650044461.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×1644400560³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308800 + ... + 314079.

It is an arithmetic number, because the mean of its divisors is an integer number (69513408).

Almost surely, 2^1644400560 is an apocalyptic number.

1644400560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644400560 is an abundant number, since it is smaller than the sum of its proper divisors (3916672080).

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

1644400560 is a wasteful number, since it uses less digits than its factorization.

1644400560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622906 (or 622900 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 1644400560 is about 40551.2091065112. The cubic root of 1644400560 is about 1180.3275352380.

It can be divided in two parts, 1644 and 400560, that added together give a palindrome (402204).

The spelling of 1644400560 in words is "one billion, six hundred forty-four million, four hundred thousand, five hundred sixty".