161616531511 has 4 divisors (see below), whose sum is σ = 162850245624. Its totient is φ = 160382817400.

The previous prime is 161616531457. The next prime is 161616531521. The reversal of 161616531511 is 115135616161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 115135616161 = 487 ⋅236418103.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161616531511 is a prime.

It is a super-2 number, since 2×161616531511² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161616531521) 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, 616856860 + ... + 616857121.

It is an arithmetic number, because the mean of its divisors is an integer number (40712561406).

Almost surely, 2^161616531511 is an apocalyptic number.

161616531511 is a deficient number, since it is larger than the sum of its proper divisors (1233714113).

161616531511 is a wasteful number, since it uses less digits than its factorization.

161616531511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1233714112.

The product of its digits is 16200, while the sum is 37.

The spelling of 161616531511 in words is "one hundred sixty-one billion, six hundred sixteen million, five hundred thirty-one thousand, five hundred eleven".