161249251 has 16 divisors (see below), whose sum is σ = 174772800. Its totient is φ = 148593984.

The previous prime is 161249213. The next prime is 161249261. The reversal of 161249251 is 152942161.

It is not a de Polignac number, because 161249251 - 2¹⁵ = 161216483 is a prime.

It is a super-2 number, since 2×161249251² = 52002641896122002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161249201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 352615 + ... + 353071.

It is an arithmetic number, because the mean of its divisors is an integer number (10923300).

Almost surely, 2^161249251 is an apocalyptic number.

161249251 is a deficient number, since it is larger than the sum of its proper divisors (13523549).

161249251 is an frugal number, since it uses more digits than its factorization.

161249251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555 (or 509 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 161249251 is about 12698.3956073198. The cubic root of 161249251 is about 544.2927739842.

The spelling of 161249251 in words is "one hundred sixty-one million, two hundred forty-nine thousand, two hundred fifty-one".