12366991 has 16 divisors (see below), whose sum is σ = 15636544. Its totient is φ = 9517824.

The previous prime is 12366989. The next prime is 12367027. The reversal of 12366991 is 19966321.

12366991 = T₁₅₄ + T₁₅₅ + ... + T₄₂₆.

It is a 8-Lehmer number, since φ(12366991) divides (12366991-1)⁸.

It is a cyclic number.

It is not a de Polignac number, because 12366991 - 2¹ = 12366989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 12366991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12366961) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1531 + ... + 5203.

It is an arithmetic number, because the mean of its divisors is an integer number (977284).

Almost surely, 2^12366991 is an apocalyptic number.

12366991 is a deficient number, since it is larger than the sum of its proper divisors (3269553).

12366991 is a wasteful number, since it uses less digits than its factorization.

12366991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3730.

The product of its digits is 17496, while the sum is 37.

The square root of 12366991 is about 3516.6732859337. The cubic root of 12366991 is about 231.2533404923.

The spelling of 12366991 in words is "twelve million, three hundred sixty-six thousand, nine hundred ninety-one".