12781000 has 32 divisors (see below), whose sum is σ = 29909880. Its totient is φ = 5112000.

The previous prime is 12780983. The next prime is 12781007. The reversal of 12781000 is 18721.

It can be written as a sum of positive squares in 4 ways, for example, as 5262436 + 7518564 = 2294^2 + 2742^2 .

It is a super-2 number, since 2×12781000² = 326707922000000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12781007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5391 + ... + 7390.

Almost surely, 2^12781000 is an apocalyptic number.

12781000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12781000 is an abundant number, since it is smaller than the sum of its proper divisors (17128880).

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

12781000 is a wasteful number, since it uses less digits than its factorization.

12781000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12802 (or 12788 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 12781000 is about 3575.0524471677. The cubic root of 12781000 is about 233.8056193726.

Adding to 12781000 its reverse (18721), we get a palindrome (12799721).

It can be divided in two parts, 1278 and 1000, that added together give a triangular number (2278 = T₆₇).

The spelling of 12781000 in words is "twelve million, seven hundred eighty-one thousand".