8131440 has 80 divisors (see below), whose sum is σ = 26703648. Its totient is φ = 2039808.

The previous prime is 8131421. The next prime is 8131463. The reversal of 8131440 is 441318.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×8131440² = 132240632947200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3084 + ... + 5076.

Almost surely, 2^8131440 is an apocalyptic number.

8131440 is a gapful number since it is divisible by the number (80) 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 8131440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13351824).

8131440 is an abundant number, since it is smaller than the sum of its proper divisors (18572208).

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

8131440 is a wasteful number, since it uses less digits than its factorization.

8131440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2026 (or 2020 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 8131440 is about 2851.5679897207. The cubic root of 8131440 is about 201.0893887206.

Adding to 8131440 its reverse (441318), we get a palindrome (8572758).

The spelling of 8131440 in words is "eight million, one hundred thirty-one thousand, four hundred forty".