12621553 has 4 divisors (see below), whose sum is σ = 14424640. Its totient is φ = 10818468.

The previous prime is 12621547. The next prime is 12621569. The reversal of 12621553 is 35512621.

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: 35512621 = 23 ⋅1544027.

It is a cyclic number.

It is not a de Polignac number, because 12621553 - 2⁹ = 12621041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12621523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 901533 + ... + 901546.

It is an arithmetic number, because the mean of its divisors is an integer number (3606160).

Almost surely, 2^12621553 is an apocalyptic number.

It is an amenable number.

12621553 is a deficient number, since it is larger than the sum of its proper divisors (1803087).

12621553 is an equidigital number, since it uses as much as digits as its factorization.

12621553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1803086.

The product of its digits is 1800, while the sum is 25.

The square root of 12621553 is about 3552.6825076272. The cubic root of 12621553 is about 232.8292817625.

The spelling of 12621553 in words is "twelve million, six hundred twenty-one thousand, five hundred fifty-three".