161564613553 has 4 divisors (see below), whose sum is σ = 184645272640. Its totient is φ = 138483954468.

The previous prime is 161564613523. The next prime is 161564613563. The reversal of 161564613553 is 355316465161.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161564613553 is a prime.

It is a super-2 number, since 2×161564613553² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161564613523) 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 3 ways as a sum of consecutive naturals, for example, 11540329533 + ... + 11540329546.

It is an arithmetic number, because the mean of its divisors is an integer number (46161318160).

Almost surely, 2^161564613553 is an apocalyptic number.

It is an amenable number.

161564613553 is a deficient number, since it is larger than the sum of its proper divisors (23080659087).

161564613553 is an equidigital number, since it uses as much as digits as its factorization.

161564613553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23080659086.

The product of its digits is 972000, while the sum is 46.

The spelling of 161564613553 in words is "one hundred sixty-one billion, five hundred sixty-four million, six hundred thirteen thousand, five hundred fifty-three".