251220163 has 4 divisors (see below), whose sum is σ = 251512128. Its totient is φ = 250928200.

The previous prime is 251220157. The next prime is 251220173. The reversal of 251220163 is 361022152.

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 251220163 - 2⁹ = 251219651 is a prime.

It is a super-2 number, since 2×251220163² = 126223140595493138, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251220103) 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, 144688 + ... + 146413.

It is an arithmetic number, because the mean of its divisors is an integer number (62878032).

Almost surely, 2^251220163 is an apocalyptic number.

251220163 is a deficient number, since it is larger than the sum of its proper divisors (291965).

251220163 is an equidigital number, since it uses as much as digits as its factorization.

251220163 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291964.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 251220163 is about 15849.9262774311. The cubic root of 251220163 is about 630.9837348034.

The spelling of 251220163 in words is "two hundred fifty-one million, two hundred twenty thousand, one hundred sixty-three".