12661578 has 24 divisors (see below), whose sum is σ = 28319616. Its totient is φ = 4084200.

The previous prime is 12661499. The next prime is 12661589. The reversal of 12661578 is 87516621.

12661578 is a `hidden beast` number, since 1 + 26 + 61 + 578 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10788 + ... + 11903.

It is an arithmetic number, because the mean of its divisors is an integer number (1179984).

Almost surely, 2^12661578 is an apocalyptic number.

12661578 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

12661578 is an abundant number, since it is smaller than the sum of its proper divisors (15658038).

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

12661578 is a wasteful number, since it uses less digits than its factorization.

12661578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22730 (or 22727 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 12661578 is about 3558.3111162460. The cubic root of 12661578 is about 233.0751352546.

The spelling of 12661578 in words is "twelve million, six hundred sixty-one thousand, five hundred seventy-eight".