161685487 has 4 divisors (see below), whose sum is σ = 171196416. Its totient is φ = 152174560.

The previous prime is 161685473. The next prime is 161685551. The reversal of 161685487 is 784586161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 784586161 = 31 ⋅25309231.

It is a cyclic number.

It is not a de Polignac number, because 161685487 - 2²³ = 153296879 is a prime.

It is a super-2 number, since 2×161685487² = 52284393412854338, which 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 (161685287) 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, 4755439 + ... + 4755472.

It is an arithmetic number, because the mean of its divisors is an integer number (42799104).

Almost surely, 2^161685487 is an apocalyptic number.

161685487 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

161685487 is a deficient number, since it is larger than the sum of its proper divisors (9510929).

161685487 is an equidigital number, since it uses as much as digits as its factorization.

161685487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9510928.

The product of its digits is 322560, while the sum is 46.

The square root of 161685487 is about 12715.5608212929. The cubic root of 161685487 is about 544.7831665548.

The spelling of 161685487 in words is "one hundred sixty-one million, six hundred eighty-five thousand, four hundred eighty-seven".