1291531392 has 112 divisors (see below), whose sum is σ = 3857973030. Its totient is φ = 430479360.

The previous prime is 1291531379. The next prime is 1291531399. The reversal of 1291531392 is 2931351921.

1291531392 is a `hidden beast` number, since 1 + 2 + 91 + 531 + 39 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1179510336 + 112021056 = 34344^2 + 10584^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291531399) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 86392 + ... + 100232.

Almost surely, 2^1291531392 is an apocalyptic number.

1291531392 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 1291531392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1928986515).

1291531392 is an abundant number, since it is smaller than the sum of its proper divisors (2566441638).

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

1291531392 is an frugal number, since it uses more digits than its factorization.

1291531392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13873 (or 13846 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 1291531392 is about 35937.8824084002. The cubic root of 1291531392 is about 1089.0178263594.

The spelling of 1291531392 in words is "one billion, two hundred ninety-one million, five hundred thirty-one thousand, three hundred ninety-two".