915253842721 has 3 divisors (see below), whose sum is σ = 915254799411. Its totient is φ = 915252886032.

The previous prime is 915253842689. The next prime is 915253842757. The reversal of 915253842721 is 127248352519.

The square root of 915253842721 is 956689.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 439981482721 + 475272360000 = 663311^2 + 689400^2 .

It is not a de Polignac number, because 915253842721 - 2⁵ = 915253842689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (915253842761) 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 2 ways as a sum of consecutive naturals, for example, 478345 + ... + 1435033.

It is an arithmetic number, because the mean of its divisors is an integer number (305084933137).

Almost surely, 2^915253842721 is an apocalyptic number.

915253842721 is the 956689-th square number.

915253842721 is the 478345-th centered octagonal number.

It is an amenable number.

915253842721 is a deficient number, since it is larger than the sum of its proper divisors (956690).

915253842721 is an frugal number, since it uses more digits than its factorization.

915253842721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1913378 (or 956689 counting only the distinct ones).

The product of its digits is 1209600, while the sum is 49.

Multiplying 915253842721 by its sum of digits (49), we get a square (44847438293329 = 6696823²).

The spelling of 915253842721 in words is "nine hundred fifteen billion, two hundred fifty-three million, eight hundred forty-two thousand, seven hundred twenty-one".