10020520721 has 4 divisors (see below), whose sum is σ = 10059511332. Its totient is φ = 9981530112.

The previous prime is 10020520709. The next prime is 10020520723. The reversal of 10020520721 is 12702502001.

10020520721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9142228225 + 878292496 = 95615^2 + 29636^2 .

It is a cyclic number.

It is not a de Polignac number, because 10020520721 - 2²⁶ = 9953411857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10020520693 and 10020520702.

It is not an unprimeable number, because it can be changed into a prime (10020520723) 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, 19494920 + ... + 19495433.

It is an arithmetic number, because the mean of its divisors is an integer number (2514877833).

Almost surely, 2^10020520721 is an apocalyptic number.

It is an amenable number.

10020520721 is a deficient number, since it is larger than the sum of its proper divisors (38990611).

10020520721 is an equidigital number, since it uses as much as digits as its factorization.

10020520721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38990610.

The product of its (nonzero) digits is 280, while the sum is 20.

The spelling of 10020520721 in words is "ten billion, twenty million, five hundred twenty thousand, seven hundred twenty-one".