12597991 has 4 divisors (see below), whose sum is σ = 14397712. Its totient is φ = 10798272.

The previous prime is 12597971. The next prime is 12598013. The reversal of 12597991 is 19979521.

12597991 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 12597991 - 2⁷ = 12597863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12597911) 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, 899850 + ... + 899863.

It is an arithmetic number, because the mean of its divisors is an integer number (3599428).

Almost surely, 2^12597991 is an apocalyptic number.

12597991 is a deficient number, since it is larger than the sum of its proper divisors (1799721).

12597991 is an equidigital number, since it uses as much as digits as its factorization.

12597991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1799720.

The product of its digits is 51030, while the sum is 43.

The square root of 12597991 is about 3549.3648727624. The cubic root of 12597991 is about 232.6843090902.

The spelling of 12597991 in words is "twelve million, five hundred ninety-seven thousand, nine hundred ninety-one".