1271891712 has 144 divisors (see below), whose sum is σ = 4166489600. Its totient is φ = 335425536.

The previous prime is 1271891701. The next prime is 1271891713. The reversal of 1271891712 is 2171981721.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1271891713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60789 + ... + 78987.

Almost surely, 2^1271891712 is an apocalyptic number.

1271891712 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 1271891712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2083244800).

1271891712 is an abundant number, since it is smaller than the sum of its proper divisors (2894597888).

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

1271891712 is a wasteful number, since it uses less digits than its factorization.

1271891712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18238 (or 18224 counting only the distinct ones).

The product of its digits is 14112, while the sum is 39.

The square root of 1271891712 is about 35663.5908455669. The cubic root of 1271891712 is about 1083.4695552464.

Subtracting 1271891712 from its reverse (2171981721), we obtain a palindrome (900090009).

The spelling of 1271891712 in words is "one billion, two hundred seventy-one million, eight hundred ninety-one thousand, seven hundred twelve".