1251111312 has 160 divisors (see below), whose sum is σ = 4088309760. Its totient is φ = 362609280.

The previous prime is 1251111271. The next prime is 1251111317. The reversal of 1251111312 is 2131111521.

It is a super-2 number, since 2×1251111312² = 3130559030028722688, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (1251111317) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 103573 + ... + 115019.

It is an arithmetic number, because the mean of its divisors is an integer number (25551936).

Almost surely, 2^1251111312 is an apocalyptic number.

1251111312 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 1251111312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2044154880).

1251111312 is an abundant number, since it is smaller than the sum of its proper divisors (2837198448).

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

1251111312 is a wasteful number, since it uses less digits than its factorization.

1251111312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11498 (or 11486 counting only the distinct ones).

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

The square root of 1251111312 is about 35371.0518927555. The cubic root of 1251111312 is about 1077.5364836745.

Adding to 1251111312 its reverse (2131111521), we get a palindrome (3382222833).

The spelling of 1251111312 in words is "one billion, two hundred fifty-one million, one hundred eleven thousand, three hundred twelve".