161538257 has 4 divisors (see below), whose sum is σ = 161564160. Its totient is φ = 161512356.

The previous prime is 161538253. The next prime is 161538281. The reversal of 161538257 is 752835161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161538257 - 2² = 161538253 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161538257.

It is not an unprimeable number, because it can be changed into a prime (161538253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2744 + ... + 18182.

It is an arithmetic number, because the mean of its divisors is an integer number (40391040).

Almost surely, 2^161538257 is an apocalyptic number.

It is an amenable number.

161538257 is a deficient number, since it is larger than the sum of its proper divisors (25903).

161538257 is a wasteful number, since it uses less digits than its factorization.

161538257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25902.

The product of its digits is 50400, while the sum is 38.

The square root of 161538257 is about 12709.7701395423. The cubic root of 161538257 is about 544.6177573907.

The spelling of 161538257 in words is "one hundred sixty-one million, five hundred thirty-eight thousand, two hundred fifty-seven".