12545721553 has 4 divisors (see below), whose sum is σ = 12551666688. Its totient is φ = 12539776420.

The previous prime is 12545721541. The next prime is 12545721563. The reversal of 12545721553 is 35512754521.

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: 35512754521 = 1201 ⋅29569321.

It is a cyclic number.

It is not a de Polignac number, because 12545721553 - 2⁵ = 12545721521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12545721563) 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, 2969401 + ... + 2973622.

It is an arithmetic number, because the mean of its divisors is an integer number (3137916672).

Almost surely, 2^12545721553 is an apocalyptic number.

It is an amenable number.

12545721553 is a deficient number, since it is larger than the sum of its proper divisors (5945135).

12545721553 is an equidigital number, since it uses as much as digits as its factorization.

12545721553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5945134.

The product of its digits is 210000, while the sum is 40.

The spelling of 12545721553 in words is "twelve billion, five hundred forty-five million, seven hundred twenty-one thousand, five hundred fifty-three".