13121840 has 20 divisors (see below), whose sum is σ = 30508464. Its totient is φ = 5248704.

The previous prime is 13121839. The next prime is 13121851. The reversal of 13121840 is 4812131.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81932 + ... + 82091.

Almost surely, 2^13121840 is an apocalyptic number.

13121840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13121840 is an abundant number, since it is smaller than the sum of its proper divisors (17386624).

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

13121840 is a wasteful number, since it uses less digits than its factorization.

13121840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164036 (or 164030 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 13121840 is about 3622.4080388603. The cubic root of 13121840 is about 235.8657668132.

Adding to 13121840 its reverse (4812131), we get a palindrome (17933971).

The spelling of 13121840 in words is "thirteen million, one hundred twenty-one thousand, eight hundred forty".