12785721 has 8 divisors (see below), whose sum is σ = 18359040. Its totient is φ = 7868112.

The previous prime is 12785711. The next prime is 12785741. The reversal of 12785721 is 12758721.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12785721 - 2⁷ = 12785593 is a prime.

It is a super-2 number, since 2×12785721² = 326949322979682, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12785701) 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, 163881 + ... + 163958.

It is an arithmetic number, because the mean of its divisors is an integer number (2294880).

Almost surely, 2^12785721 is an apocalyptic number.

It is an amenable number.

12785721 is a deficient number, since it is larger than the sum of its proper divisors (5573319).

12785721 is a wasteful number, since it uses less digits than its factorization.

12785721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327855.

The product of its digits is 7840, while the sum is 33.

The square root of 12785721 is about 3575.7126562407. The cubic root of 12785721 is about 233.8344032563.

Subtracting from 12785721 its reverse (12758721), we obtain a cube (27000 = 30³).

The spelling of 12785721 in words is "twelve million, seven hundred eighty-five thousand, seven hundred twenty-one".