12991553 has 4 divisors (see below), whose sum is σ = 13755780. Its totient is φ = 12227328.

The previous prime is 12991543. The next prime is 12991567. The reversal of 12991553 is 35519921.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8862529 + 4129024 = 2977^2 + 2032^2 .

It is a cyclic number.

It is not a de Polignac number, because 12991553 - 2²⁰ = 11942977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12991513) 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, 382088 + ... + 382121.

It is an arithmetic number, because the mean of its divisors is an integer number (3438945).

Almost surely, 2^12991553 is an apocalyptic number.

It is an amenable number.

12991553 is a deficient number, since it is larger than the sum of its proper divisors (764227).

12991553 is an equidigital number, since it uses as much as digits as its factorization.

12991553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764226.

The product of its digits is 12150, while the sum is 35.

The square root of 12991553 is about 3604.3796969798. The cubic root of 12991553 is about 235.0825302400.

The spelling of 12991553 in words is "twelve million, nine hundred ninety-one thousand, five hundred fifty-three".