161500406 has 4 divisors (see below), whose sum is σ = 242250612. Its totient is φ = 80750202.

The previous prime is 161500397. The next prime is 161500453. The reversal of 161500406 is 604005161.

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

It is a super-2 number, since 2×161500406² = 52164762276329672, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40375100 + ... + 40375103.

It is an arithmetic number, because the mean of its divisors is an integer number (60562653).

Almost surely, 2^161500406 is an apocalyptic number.

161500406 is a deficient number, since it is larger than the sum of its proper divisors (80750206).

161500406 is an equidigital number, since it uses as much as digits as its factorization.

161500406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80750205.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 161500406 is about 12708.2810009851. The cubic root of 161500406 is about 544.5752165144.

Adding to 161500406 its reverse (604005161), we get a palindrome (765505567).

The spelling of 161500406 in words is "one hundred sixty-one million, five hundred thousand, four hundred six".