161503213 has 4 divisors (see below), whose sum is σ = 171003420. Its totient is φ = 152003008.

The previous prime is 161503201. The next prime is 161503241. The reversal of 161503213 is 312305161.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 121396324 + 40106889 = 11018^2 + 6333^2 .

It is a cyclic number.

It is not a de Polignac number, because 161503213 - 2⁹ = 161502701 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 (161503613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4750078 + ... + 4750111.

It is an arithmetic number, because the mean of its divisors is an integer number (42750855).

Almost surely, 2^161503213 is an apocalyptic number.

It is an amenable number.

161503213 is a deficient number, since it is larger than the sum of its proper divisors (9500207).

161503213 is an equidigital number, since it uses as much as digits as its factorization.

161503213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9500206.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 161503213 is about 12708.3914403043. The cubic root of 161503213 is about 544.5783715401.

Adding to 161503213 its reverse (312305161), we get a palindrome (473808374).

The spelling of 161503213 in words is "one hundred sixty-one million, five hundred three thousand, two hundred thirteen".