161313538 has 4 divisors (see below), whose sum is σ = 241970310. Its totient is φ = 80656768.

The previous prime is 161313533. The next prime is 161313539. The reversal of 161313538 is 835313161.

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

It can be written as a sum of positive squares in only one way, i.e., 154927809 + 6385729 = 12447^2 + 2527^2 .

It is not an unprimeable number, because it can be changed into a prime (161313533) by changing a digit.

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, 40328383 + ... + 40328386.

Almost surely, 2^161313538 is an apocalyptic number.

161313538 is a deficient number, since it is larger than the sum of its proper divisors (80656772).

161313538 is an equidigital number, since it uses as much as digits as its factorization.

161313538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80656771.

The product of its digits is 6480, while the sum is 31.

The square root of 161313538 is about 12700.9266591064. The cubic root of 161313538 is about 544.3650974220.

Adding to 161313538 its reverse (835313161), we get a palindrome (996626699).

It can be divided in two parts, 1613 and 13538, that added together give a palindrome (15151).

The spelling of 161313538 in words is "one hundred sixty-one million, three hundred thirteen thousand, five hundred thirty-eight".