161561011497 has 4 divisors (see below), whose sum is σ = 215414682000. Its totient is φ = 107707340996.

The previous prime is 161561011483. The next prime is 161561011517. The reversal of 161561011497 is 794110165161.

161561011497 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 Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 794110165161 = 3 ⋅264703388387.

It is a cyclic number.

It is not a de Polignac number, because 161561011497 - 2³¹ = 159413527849 is a prime.

It is a super-2 number, since 2×161561011497² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161561011397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26926835247 + ... + 26926835252.

It is an arithmetic number, because the mean of its divisors is an integer number (53853670500).

Almost surely, 2^161561011497 is an apocalyptic number.

It is an amenable number.

161561011497 is a deficient number, since it is larger than the sum of its proper divisors (53853670503).

161561011497 is an equidigital number, since it uses as much as digits as its factorization.

161561011497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53853670502.

The product of its (nonzero) digits is 45360, while the sum is 42.

The spelling of 161561011497 in words is "one hundred sixty-one billion, five hundred sixty-one million, eleven thousand, four hundred ninety-seven".