13218440 has 32 divisors (see below), whose sum is σ = 29873880. Its totient is φ = 5263872.

The previous prime is 13218409. The next prime is 13218463. The reversal of 13218440 is 4481231.

It can be written as a sum of positive squares in 4 ways, for example, as 8561476 + 4656964 = 2926^2 + 2158^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10484 + ... + 11676.

Almost surely, 2^13218440 is an apocalyptic number.

13218440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13218440 is an abundant number, since it is smaller than the sum of its proper divisors (16655440).

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

13218440 is a wasteful number, since it uses less digits than its factorization.

13218440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481 (or 1477 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 13218440 is about 3635.7172607341. The cubic root of 13218440 is about 236.4431489707.

Adding to 13218440 its reverse (4481231), we get a palindrome (17699671).

The spelling of 13218440 in words is "thirteen million, two hundred eighteen thousand, four hundred forty".