12999981 has 4 divisors (see below), whose sum is σ = 17333312. Its totient is φ = 8666652.

The previous prime is 12999979. The next prime is 12999983. The reversal of 12999981 is 18999921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18999921 = 3 ⋅6333307.

It is an interprime number because it is at equal distance from previous prime (12999979) and next prime (12999983).

It is not a de Polignac number, because 12999981 - 2¹ = 12999979 is a prime.

It is a super-2 number, since 2×12999981² = 337999012000722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12999981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12999983) 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 3 ways as a sum of consecutive naturals, for example, 2166661 + ... + 2166666.

It is an arithmetic number, because the mean of its divisors is an integer number (4333328).

Almost surely, 2^12999981 is an apocalyptic number.

It is an amenable number.

12999981 is a deficient number, since it is larger than the sum of its proper divisors (4333331).

12999981 is an equidigital number, since it uses as much as digits as its factorization.

12999981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4333330.

The product of its digits is 104976, while the sum is 48.

The square root of 12999981 is about 3605.5486406371. The cubic root of 12999981 is about 235.1333542198.

The spelling of 12999981 in words is "twelve million, nine hundred ninety-nine thousand, nine hundred eighty-one".