13581640 has 32 divisors (see below), whose sum is σ = 32357880. Its totient is φ = 5112832.

The previous prime is 13581629. The next prime is 13581641. The reversal of 13581640 is 4618531.

It can be written as a sum of positive squares in 4 ways, for example, as 11737476 + 1844164 = 3426^2 + 1358^2 .

It is a junction number, because it is equal to n+sod(n) for n = 13581599 and 13581608.

It is not an unprimeable number, because it can be changed into a prime (13581641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9307 + ... + 10666.

Almost surely, 2^13581640 is an apocalyptic number.

13581640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13581640 is an abundant number, since it is smaller than the sum of its proper divisors (18776240).

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

13581640 is a wasteful number, since it uses less digits than its factorization.

13581640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20001 (or 19997 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 13581640 is about 3685.3276652151. The cubic root of 13581640 is about 238.5891765258.

The spelling of 13581640 in words is "thirteen million, five hundred eighty-one thousand, six hundred forty".