997250795521 has 4 divisors (see below), whose sum is σ = 998568168532. Its totient is φ = 995933422512.

The previous prime is 997250795509. The next prime is 997250795537. The reversal of 997250795521 is 125597052799.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125597052799 = 43 ⋅2920861693.

It can be written as a sum of positive squares in 2 ways, for example, as 448116442225 + 549134353296 = 669415^2 + 741036^2 .

It is a cyclic number.

It is not a de Polignac number, because 997250795521 - 2⁷ = 997250795393 is a prime.

It is a super-2 number, since 2×997250795521² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 997250795521.

It is not an unprimeable number, because it can be changed into a prime (997250795561) 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, 658685370 + ... + 658686883.

It is an arithmetic number, because the mean of its divisors is an integer number (249642042133).

Almost surely, 2^997250795521 is an apocalyptic number.

It is an amenable number.

997250795521 is a deficient number, since it is larger than the sum of its proper divisors (1317373011).

997250795521 is a wasteful number, since it uses less digits than its factorization.

997250795521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1317373010.

The product of its (nonzero) digits is 17860500, while the sum is 61.

The spelling of 997250795521 in words is "nine hundred ninety-seven billion, two hundred fifty million, seven hundred ninety-five thousand, five hundred twenty-one".