12721018 has 4 divisors (see below), whose sum is σ = 19081530. Its totient is φ = 6360508.

The previous prime is 12720997. The next prime is 12721019. The reversal of 12721018 is 81012721.

12721018 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81012721 = 37 ⋅2189533.

It can be written as a sum of positive squares in only one way, i.e., 6385729 + 6335289 = 2527^2 + 2517^2 .

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 12721018.

It is not an unprimeable number, because it can be changed into a prime (12721019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3180253 + ... + 3180256.

Almost surely, 2^12721018 is an apocalyptic number.

12721018 is a deficient number, since it is larger than the sum of its proper divisors (6360512).

12721018 is an equidigital number, since it uses as much as digits as its factorization.

12721018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6360511.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 12721018 is about 3566.6536136833. The cubic root of 12721018 is about 233.4392911058.

Adding to 12721018 its reverse (81012721), we get a palindrome (93733739).

The spelling of 12721018 in words is "twelve million, seven hundred twenty-one thousand, eighteen".