917838725521 has 3 divisors (see below), whose sum is σ = 917839683561. Its totient is φ = 917837767482.

The previous prime is 917838725497. The next prime is 917838725527. The reversal of 917838725521 is 125527838719.

It is a happy number.

The square root of 917838725521 is 958039.

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

917838725521 is digitally balanced in base 2, 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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 125527838719 = 6197 ⋅20256227.

It is a de Polignac number, because none of the positive numbers 2^k-917838725521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (917838725527) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 479020 + ... + 1437058.

It is an arithmetic number, because the mean of its divisors is an integer number (305946561187).

Almost surely, 2^917838725521 is an apocalyptic number.

917838725521 is the 958039-th square number.

917838725521 is the 479020-th centered octagonal number.

It is an amenable number.

917838725521 is a deficient number, since it is larger than the sum of its proper divisors (958040).

917838725521 is an frugal number, since it uses more digits than its factorization.

917838725521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1916078 (or 958039 counting only the distinct ones).

The product of its digits is 8467200, while the sum is 58.

The spelling of 917838725521 in words is "nine hundred seventeen billion, eight hundred thirty-eight million, seven hundred twenty-five thousand, five hundred twenty-one".