12722781 has 4 divisors (see below), whose sum is σ = 16963712. Its totient is φ = 8481852.

The previous prime is 12722771. The next prime is 12722791. The reversal of 12722781 is 18722721.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (12722771) and next prime (12722791).

It is not a de Polignac number, because 12722781 - 2⁷ = 12722653 is a prime.

It is a super-2 number, since 2×12722781² = 323738312747922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12722771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2120461 + ... + 2120466.

It is an arithmetic number, because the mean of its divisors is an integer number (4240928).

Almost surely, 2^12722781 is an apocalyptic number.

It is an amenable number.

12722781 is a deficient number, since it is larger than the sum of its proper divisors (4240931).

12722781 is an equidigital number, since it uses as much as digits as its factorization.

12722781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4240930.

The product of its digits is 3136, while the sum is 30.

The square root of 12722781 is about 3566.9007555580. The cubic root of 12722781 is about 233.4500746888.

The spelling of 12722781 in words is "twelve million, seven hundred twenty-two thousand, seven hundred eighty-one".