10561015721 has 4 divisors (see below), whose sum is σ = 10561794432. Its totient is φ = 10560237012.

The previous prime is 10561015687. The next prime is 10561015739. The reversal of 10561015721 is 12751016501.

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: 12751016501 = 53 ⋅240585217.

It is a cyclic number.

It is not a de Polignac number, because 10561015721 - 2²² = 10556821417 is a prime.

It is a super-2 number, since 2×10561015721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10561015741) 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, 368645 + ... + 396258.

It is an arithmetic number, because the mean of its divisors is an integer number (2640448608).

Almost surely, 2^10561015721 is an apocalyptic number.

It is an amenable number.

10561015721 is a deficient number, since it is larger than the sum of its proper divisors (778711).

10561015721 is an equidigital number, since it uses as much as digits as its factorization.

10561015721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778710.

The product of its (nonzero) digits is 2100, while the sum is 29.

The spelling of 10561015721 in words is "ten billion, five hundred sixty-one million, fifteen thousand, seven hundred twenty-one".