10121505721 has 4 divisors (see below), whose sum is σ = 10144048500. Its totient is φ = 10098962944.

The previous prime is 10121505671. The next prime is 10121505739. The reversal of 10121505721 is 12750512101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12750512101 = 1721 ⋅7408781.

It can be written as a sum of positive squares in 2 ways, for example, as 2388765625 + 7732740096 = 48875^2 + 87936^2 .

It is a cyclic number.

It is not a de Polignac number, because 10121505721 - 2¹⁵ = 10121472953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10121508721) 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, 11270716 + ... + 11271613.

It is an arithmetic number, because the mean of its divisors is an integer number (2536012125).

Almost surely, 2^10121505721 is an apocalyptic number.

It is an amenable number.

10121505721 is a deficient number, since it is larger than the sum of its proper divisors (22542779).

10121505721 is an equidigital number, since it uses as much as digits as its factorization.

10121505721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22542778.

The product of its (nonzero) digits is 700, while the sum is 25.

The spelling of 10121505721 in words is "ten billion, one hundred twenty-one million, five hundred five thousand, seven hundred twenty-one".