251066591 has 4 divisors (see below), whose sum is σ = 265835232. Its totient is φ = 236297952.

The previous prime is 251066581. The next prime is 251066603. The reversal of 251066591 is 195660152.

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 251066591 - 2¹⁰ = 251065567 is a prime.

It is a super-2 number, since 2×251066591² = 126068866232722562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251066521) 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, 7384295 + ... + 7384328.

It is an arithmetic number, because the mean of its divisors is an integer number (66458808).

Almost surely, 2^251066591 is an apocalyptic number.

251066591 is a deficient number, since it is larger than the sum of its proper divisors (14768641).

251066591 is a wasteful number, since it uses less digits than its factorization.

251066591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14768640.

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 251066591 is about 15845.0809717085. The cubic root of 251066591 is about 630.8551342098.

The spelling of 251066591 in words is "two hundred fifty-one million, sixty-six thousand, five hundred ninety-one".