161616531 has 4 divisors (see below), whose sum is σ = 215488712. Its totient is φ = 107744352.

The previous prime is 161616491. The next prime is 161616577. The reversal of 161616531 is 135616161.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 161616531 - 2⁹ = 161616019 is a prime.

It is a super-2 number, since 2×161616531² = 52239806184947922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161616031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26936086 + ... + 26936091.

It is an arithmetic number, because the mean of its divisors is an integer number (53872178).

Almost surely, 2^161616531 is an apocalyptic number.

161616531 is a deficient number, since it is larger than the sum of its proper divisors (53872181).

161616531 is an equidigital number, since it uses as much as digits as its factorization.

161616531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53872180.

The product of its digits is 3240, while the sum is 30.

The square root of 161616531 is about 12712.8490512552. The cubic root of 161616531 is about 544.7057087478.

The spelling of 161616531 in words is "one hundred sixty-one million, six hundred sixteen thousand, five hundred thirty-one".