12139681 has 4 divisors (see below), whose sum is σ = 12306052. Its totient is φ = 11973312.

The previous prime is 12139679. The next prime is 12139691. The reversal of 12139681 is 18693121.

12139681 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: 18693121 = 829 ⋅22549.

It can be written as a sum of positive squares in 2 ways, for example, as 4389025 + 7750656 = 2095^2 + 2784^2 .

It is a cyclic number.

It is not a de Polignac number, because 12139681 - 2¹ = 12139679 is a prime.

It is a super-2 number, since 2×12139681² = 294743709563522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12139691) 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, 83076 + ... + 83221.

It is an arithmetic number, because the mean of its divisors is an integer number (3076513).

Almost surely, 2^12139681 is an apocalyptic number.

It is an amenable number.

12139681 is a deficient number, since it is larger than the sum of its proper divisors (166371).

12139681 is an equidigital number, since it uses as much as digits as its factorization.

12139681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166370.

The product of its digits is 2592, while the sum is 31.

The square root of 12139681 is about 3484.2045003128. The cubic root of 12139681 is about 229.8277285928.

The spelling of 12139681 in words is "twelve million, one hundred thirty-nine thousand, six hundred eighty-one".