12139661 has 6 divisors (see below), whose sum is σ = 12577710. Its totient is φ = 11702936.

The previous prime is 12139637. The next prime is 12139679. The reversal of 12139661 is 16693121.

It can be written as a sum of positive squares in only one way, i.e., 10465225 + 1674436 = 3235^2 + 1294^2 .

It is a de Polignac number, because none of the positive numbers 2^k-12139661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12139691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18440 + ... + 19086.

It is an arithmetic number, because the mean of its divisors is an integer number (2096285).

Almost surely, 2^12139661 is an apocalyptic number.

It is an amenable number.

12139661 is a deficient number, since it is larger than the sum of its proper divisors (438049).

12139661 is an frugal number, since it uses more digits than its factorization.

12139661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1323 (or 676 counting only the distinct ones).

The product of its digits is 1944, while the sum is 29.

The square root of 12139661 is about 3484.2016302160. The cubic root of 12139661 is about 229.8276023798.

Multiplying 12139661 by its sum of digits (29), we get a square (352050169 = 18763²).

12139661 divided by its sum of digits (29) gives a square (418609 = 647²).

The spelling of 12139661 in words is "twelve million, one hundred thirty-nine thousand, six hundred sixty-one".