66251 has 4 divisors (see below), whose sum is σ = 67032. Its totient is φ = 65472.

The previous prime is 66239. The next prime is 66271. The reversal of 66251 is 15266.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66251 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66251.

It is not an unprimeable number, because it can be changed into a prime (66221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245 + ... + 438.

It is an arithmetic number, because the mean of its divisors is an integer number (16758).

2⁶⁶²⁵¹ is an apocalyptic number.

66251 is a deficient number, since it is larger than the sum of its proper divisors (781).

66251 is an equidigital number, since it uses as much as digits as its factorization.

66251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 780.

The product of its digits is 360, while the sum is 20.

The square root of 66251 is about 257.3926960891. The cubic root of 66251 is about 40.4635652610.

The spelling of 66251 in words is "sixty-six thousand, two hundred fifty-one".