1661056320 has 448 divisors, whose sum is σ = 6868094976. Its totient is φ = 329809920.

The previous prime is 1661056303. The next prime is 1661056373. The reversal of 1661056320 is 236501661.

It is a tau number, because it is divible by the number of its divisors (448).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1699672 + ... + 1700648.

Almost surely, 2^1661056320 is an apocalyptic number.

1661056320 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 1661056320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3434047488).

1661056320 is an abundant number, since it is smaller than the sum of its proper divisors (5207038656).

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

1661056320 is a wasteful number, since it uses less digits than its factorization.

1661056320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1038 (or 1028 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 1661056320 is about 40756.0586907027. The cubic root of 1661056320 is about 1184.2992456426.

Adding to 1661056320 its reverse (236501661), we get a palindrome (1897557981).

The spelling of 1661056320 in words is "one billion, six hundred sixty-one million, fifty-six thousand, three hundred twenty".