161531533 has 8 divisors (see below), whose sum is σ = 162962208. Its totient is φ = 160106544.

The previous prime is 161531497. The next prime is 161531551. The reversal of 161531533 is 335135161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161531533 - 2¹⁷ = 161400461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161531593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71091 + ... + 73327.

It is an arithmetic number, because the mean of its divisors is an integer number (20370276).

Almost surely, 2^161531533 is an apocalyptic number.

It is an amenable number.

161531533 is a deficient number, since it is larger than the sum of its proper divisors (1430675).

161531533 is a wasteful number, since it uses less digits than its factorization.

161531533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843.

The product of its digits is 4050, while the sum is 28.

The square root of 161531533 is about 12709.5056158766. The cubic root of 161531533 is about 544.6102007482.

Adding to 161531533 its reverse (335135161), we get a palindrome (496666694).

The spelling of 161531533 in words is "one hundred sixty-one million, five hundred thirty-one thousand, five hundred thirty-three".