12689440 has 24 divisors (see below), whose sum is σ = 29979180. Its totient is φ = 5075712.

The previous prime is 12689423. The next prime is 12689477. The reversal of 12689440 is 4498621.

It can be written as a sum of positive squares in 2 ways, for example, as 12362256 + 327184 = 3516^2 + 572^2 .

It is a super-2 number, since 2×12689440² = 322043775027200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 12689396 and 12689405.

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, 39495 + ... + 39814.

Almost surely, 2^12689440 is an apocalyptic number.

12689440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12689440 is an abundant number, since it is smaller than the sum of its proper divisors (17289740).

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

12689440 is an equidigital number, since it uses as much as digits as its factorization.

12689440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79324 (or 79316 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 12689440 is about 3562.2240243982. The cubic root of 12689440 is about 233.2459718305.

The spelling of 12689440 in words is "twelve million, six hundred eighty-nine thousand, four hundred forty".