15453325721 has 4 divisors (see below), whose sum is σ = 16125209472. Its totient is φ = 14781441972.

The previous prime is 15453325709. The next prime is 15453325733. The reversal of 15453325721 is 12752335451.

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.

It is an interprime number because it is at equal distance from previous prime (15453325709) and next prime (15453325733).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15453325721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15453325781) 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, 335941841 + ... + 335941886.

It is an arithmetic number, because the mean of its divisors is an integer number (4031302368).

Almost surely, 2^15453325721 is an apocalyptic number.

It is an amenable number.

15453325721 is a deficient number, since it is larger than the sum of its proper divisors (671883751).

15453325721 is an equidigital number, since it uses as much as digits as its factorization.

15453325721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671883750.

The product of its digits is 126000, while the sum is 38.

The spelling of 15453325721 in words is "fifteen billion, four hundred fifty-three million, three hundred twenty-five thousand, seven hundred twenty-one".