161445531 has 24 divisors (see below), whose sum is σ = 234005760. Its totient is φ = 98962656.

The previous prime is 161445499. The next prime is 161445547. The reversal of 161445531 is 135544161.

It is a happy number.

It is not a de Polignac number, because 161445531 - 2⁵ = 161445499 is a prime.

It is a super-2 number, since 2×161445531² = 52129318959743922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161445631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 181570 + ... + 182456.

It is an arithmetic number, because the mean of its divisors is an integer number (9750240).

Almost surely, 2^161445531 is an apocalyptic number.

161445531 is a deficient number, since it is larger than the sum of its proper divisors (72560229).

161445531 is a wasteful number, since it uses less digits than its factorization.

161445531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1275 (or 1262 counting only the distinct ones).

The product of its digits is 7200, while the sum is 30.

The square root of 161445531 is about 12706.1217922701. The cubic root of 161445531 is about 544.5135304976.

Adding to 161445531 its reverse (135544161), we get a palindrome (296989692).

The spelling of 161445531 in words is "one hundred sixty-one million, four hundred forty-five thousand, five hundred thirty-one".