1391287888 has 40 divisors (see below), whose sum is σ = 2861020008. Its totient is φ = 653156352.

The previous prime is 1391287879. The next prime is 1391287903. The reversal of 1391287888 is 8887821931.

It can be written as a sum of positive squares in 4 ways, for example, as 94711824 + 1296576064 = 9732^2 + 36008^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111870 + ... + 123682.

Almost surely, 2^1391287888 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 1391287888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1430510004).

1391287888 is an abundant number, since it is smaller than the sum of its proper divisors (1469732120).

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

1391287888 is a wasteful number, since it uses less digits than its factorization.

1391287888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12271 (or 12265 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 55.

The square root of 1391287888 is about 37299.9716889973. The cubic root of 1391287888 is about 1116.3636015847.

The spelling of 1391287888 in words is "one billion, three hundred ninety-one million, two hundred eighty-seven thousand, eight hundred eighty-eight".