1661443056 has 240 divisors, whose sum is σ = 5903550720. Its totient is φ = 438048000.

The previous prime is 1661443051. The next prime is 1661443061. The reversal of 1661443056 is 6503441661.

It is a happy number.

1661443056 is a `hidden beast` number, since 1 + 6 + 614 + 4 + 30 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (1661443051) and next prime (1661443061).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1661443056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661443051) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 509431 + ... + 512681.

It is an arithmetic number, because the mean of its divisors is an integer number (24598128).

Almost surely, 2^1661443056 is an apocalyptic number.

1661443056 is a gapful number since it is divisible by the number (16) 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 1661443056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2951775360).

1661443056 is an abundant number, since it is smaller than the sum of its proper divisors (4242107664).

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

1661443056 is a wasteful number, since it uses less digits than its factorization.

1661443056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3301 (or 3276 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 1661443056 is about 40760.8029361542. The cubic root of 1661443056 is about 1184.3911501347.

The spelling of 1661443056 in words is "one billion, six hundred sixty-one million, four hundred forty-three thousand, fifty-six".