1211511312 has 120 divisors (see below), whose sum is σ = 3768830208. Its totient is φ = 360172800.

The previous prime is 1211511277. The next prime is 1211511317. The reversal of 1211511312 is 2131151121.

1211511312 is a `hidden beast` number, since 121 + 1 + 511 + 31 + 2 = 666.

It is a super-2 number, since 2×1211511312² = 2935519318207922688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211511317) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76737 + ... + 91167.

Almost surely, 2^1211511312 is an apocalyptic number.

1211511312 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 1211511312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1884415104).

1211511312 is an abundant number, since it is smaller than the sum of its proper divisors (2557318896).

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

1211511312 is a wasteful number, since it uses less digits than its factorization.

1211511312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14509 (or 14500 counting only the distinct ones).

The product of its digits is 60, while the sum is 18.

The square root of 1211511312 is about 34806.7710654120. The cubic root of 1211511312 is about 1066.0457043742.

Adding to 1211511312 its reverse (2131151121), we get a palindrome (3342662433).

The spelling of 1211511312 in words is "one billion, two hundred eleven million, five hundred eleven thousand, three hundred twelve".