997164013561 has 9 divisors (see below), whose sum is σ = 1006180426381. Its totient is φ = 988227712192.

The previous prime is 997164013523. The next prime is 997164013609. The reversal of 997164013561 is 165310461799.

The square root of 997164013561 is 998581.

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

It can be written as a sum of positive squares in 4 ways, for example, as 12425337961 + 984738675600 = 111469^2 + 992340^2 .

It is not a de Polignac number, because 997164013561 - 2²¹ = 997161916409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 997164013499 and 997164013508.

It is not an unprimeable number, because it can be changed into a prime (997164013961) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 112835235 + ... + 112844071.

Almost surely, 2^997164013561 is an apocalyptic number.

997164013561 is the 998581-st square number.

997164013561 is the 499291-st centered octagonal number.

It is an amenable number.

997164013561 is a deficient number, since it is larger than the sum of its proper divisors (9016412820).

997164013561 is an frugal number, since it uses more digits than its factorization.

997164013561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17900 (or 8950 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 52.

The spelling of 997164013561 in words is "nine hundred ninety-seven billion, one hundred sixty-four million, thirteen thousand, five hundred sixty-one".