161533431 has 12 divisors (see below), whose sum is σ = 233567880. Its totient is φ = 107577360.

The previous prime is 161533423. The next prime is 161533447. The reversal of 161533431 is 134335161.

161533431 is a `hidden beast` number, since 1 + 615 + 3 + 3 + 43 + 1 = 666.

It is not a de Polignac number, because 161533431 - 2³ = 161533423 is a prime.

It is a super-2 number, since 2×161533431² = 52186098661263522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161533395 and 161533404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161533331) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 400 + ... + 17978.

It is an arithmetic number, because the mean of its divisors is an integer number (19463990).

Almost surely, 2^161533431 is an apocalyptic number.

161533431 is a deficient number, since it is larger than the sum of its proper divisors (72034449).

161533431 is a wasteful number, since it uses less digits than its factorization.

161533431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18606 (or 18603 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 161533431 is about 12709.5802841793. The cubic root of 161533431 is about 544.6123338015.

Adding to 161533431 its reverse (134335161), we get a palindrome (295868592).

The spelling of 161533431 in words is "one hundred sixty-one million, five hundred thirty-three thousand, four hundred thirty-one".