161291650 has 24 divisors (see below), whose sum is σ = 323080884. Its totient is φ = 59553600.

The previous prime is 161291609. The next prime is 161291657. The reversal of 161291650 is 56192161.

It can be written as a sum of positive squares in 6 ways, for example, as 26429881 + 134861769 = 5141^2 + 11613^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (161291657) 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 in 11 ways as a sum of consecutive naturals, for example, 123421 + ... + 124720.

Almost surely, 2^161291650 is an apocalyptic number.

161291650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161291650 is an abundant number, since it is smaller than the sum of its proper divisors (161789234).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161291650 is a wasteful number, since it uses less digits than its factorization.

161291650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248166 (or 248161 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 161291650 is about 12700.0649604638. The cubic root of 161291650 is about 544.3404753881.

The spelling of 161291650 in words is "one hundred sixty-one million, two hundred ninety-one thousand, six hundred fifty".