1211728112 has 80 divisors (see below), whose sum is σ = 2791458240. Its totient is φ = 498548736.

The previous prime is 1211728069. The next prime is 1211728121. The reversal of 1211728112 is 2118271121.

It is a happy number.

It is a super-2 number, since 2×1211728112² = 2936570034822169088, which contains 22 as substring.

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

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 15 ways as a sum of consecutive naturals, for example, 625898 + ... + 627830.

It is an arithmetic number, because the mean of its divisors is an integer number (34893228).

Almost surely, 2^1211728112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211728112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1395729120).

1211728112 is an abundant number, since it is smaller than the sum of its proper divisors (1579730128).

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

1211728112 is a wasteful number, since it uses less digits than its factorization.

1211728112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2170 (or 2164 counting only the distinct ones).

The product of its digits is 448, while the sum is 26.

The square root of 1211728112 is about 34809.8852626664. The cubic root of 1211728112 is about 1066.1092902226.

Adding to 1211728112 its reverse (2118271121), we get a palindrome (3329999233).

The spelling of 1211728112 in words is "one billion, two hundred eleven million, seven hundred twenty-eight thousand, one hundred twelve".