161390251 has 4 divisors (see below), whose sum is σ = 176062104. Its totient is φ = 146718400.

The previous prime is 161390221. The next prime is 161390261. The reversal of 161390251 is 152093161.

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

It is a cyclic number.

It is not a de Polignac number, because 161390251 - 2⁵ = 161390219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161390221) 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 3 ways as a sum of consecutive naturals, for example, 7335910 + ... + 7335931.

It is an arithmetic number, because the mean of its divisors is an integer number (44015526).

Almost surely, 2^161390251 is an apocalyptic number.

161390251 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161390251 is a deficient number, since it is larger than the sum of its proper divisors (14671853).

161390251 is a wasteful number, since it uses less digits than its factorization.

161390251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14671852.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 161390251 is about 12703.9462766496. The cubic root of 161390251 is about 544.4513750780.

The spelling of 161390251 in words is "one hundred sixty-one million, three hundred ninety thousand, two hundred fifty-one".