13121640 has 192 divisors, whose sum is σ = 50319360. Its totient is φ = 2903040.

The previous prime is 13121639. The next prime is 13121657. The reversal of 13121640 is 4612131.

It is a happy number.

13121640 is a `hidden beast` number, since 1 + 3 + 1 + 21 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 103257 + ... + 103383.

It is an arithmetic number, because the mean of its divisors is an integer number (262080).

Almost surely, 2^13121640 is an apocalyptic number.

13121640 is a gapful number since it is divisible by the number (10) 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 13121640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25159680).

13121640 is an abundant number, since it is smaller than the sum of its proper divisors (37197720).

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

13121640 is a wasteful number, since it uses less digits than its factorization.

13121640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 13121640 is about 3622.3804328093. The cubic root of 13121640 is about 235.8645684703.

Adding to 13121640 its reverse (4612131), we get a palindrome (17733771).

The spelling of 13121640 in words is "thirteen million, one hundred twenty-one thousand, six hundred forty".