1020172765721 has 8 divisors (see below), whose sum is σ = 1082321710080. Its totient is φ = 958869385488.

The previous prime is 1020172765687. The next prime is 1020172765723. The reversal of 1020172765721 is 1275672710201.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1020172765721 - 2¹⁰ = 1020172764697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1020172765723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 211388546 + ... + 211393371.

It is an arithmetic number, because the mean of its divisors is an integer number (135290213760).

Almost surely, 2^{1020172765721} is an apocalyptic number.

It is an amenable number.

1020172765721 is a deficient number, since it is larger than the sum of its proper divisors (62148944359).

1020172765721 is a wasteful number, since it uses less digits than its factorization.

1020172765721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422782063.

The product of its (nonzero) digits is 82320, while the sum is 41.

The spelling of 1020172765721 in words is "one trillion, twenty billion, one hundred seventy-two million, seven hundred sixty-five thousand, seven hundred twenty-one".