1661228112 has 80 divisors (see below), whose sum is σ = 4456232640. Its totient is φ = 532632576.

The previous prime is 1661228099. The next prime is 1661228143. The reversal of 1661228112 is 2118221661.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1661228112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 391828 + ... + 396044.

It is an arithmetic number, because the mean of its divisors is an integer number (55702908).

Almost surely, 2^1661228112 is an apocalyptic number.

1661228112 is a gapful number since it is divisible by the number (12) 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 1661228112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2228116320).

1661228112 is an abundant number, since it is smaller than the sum of its proper divisors (2795004528).

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

1661228112 is a wasteful number, since it uses less digits than its factorization.

1661228112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4540 (or 4534 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 1661228112 is about 40758.1662001617. The cubic root of 1661228112 is about 1184.3400722982.

Adding to 1661228112 its reverse (2118221661), we get a palindrome (3779449773).

The spelling of 1661228112 in words is "one billion, six hundred sixty-one million, two hundred twenty-eight thousand, one hundred twelve".