12720731 has 4 divisors (see below), whose sum is σ = 12732432. Its totient is φ = 12709032.

The previous prime is 12720713. The next prime is 12720737. The reversal of 12720731 is 13702721.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 12720731 - 2¹⁴ = 12704347 is a prime.

It is a super-2 number, since 2×12720731² = 323633994348722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12720697 and 12720706.

It is not an unprimeable number, because it can be changed into a prime (12720737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4031 + ... + 6456.

It is an arithmetic number, because the mean of its divisors is an integer number (3183108).

Almost surely, 2^12720731 is an apocalyptic number.

12720731 is a deficient number, since it is larger than the sum of its proper divisors (11701).

12720731 is a wasteful number, since it uses less digits than its factorization.

12720731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11700.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 12720731 is about 3566.6133796642. The cubic root of 12720731 is about 233.4375355445.

The spelling of 12720731 in words is "twelve million, seven hundred twenty thousand, seven hundred thirty-one".