13121440 has 24 divisors (see below), whose sum is σ = 30999780. Its totient is φ = 5248512.

The previous prime is 13121429. The next prime is 13121441. The reversal of 13121440 is 4412131.

It can be written as a sum of positive squares in 2 ways, for example, as 12475024 + 646416 = 3532^2 + 804^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40845 + ... + 41164.

Almost surely, 2^13121440 is an apocalyptic number.

13121440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13121440 is an abundant number, since it is smaller than the sum of its proper divisors (17878340).

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

13121440 is an equidigital number, since it uses as much as digits as its factorization.

13121440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82024 (or 82016 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 13121440 is about 3622.3528265480. The cubic root of 13121440 is about 235.8633701152.

Adding to 13121440 its reverse (4412131), we get a palindrome (17533571).

The spelling of 13121440 in words is "thirteen million, one hundred twenty-one thousand, four hundred forty".