251005 has 8 divisors (see below), whose sum is σ = 319032. Its totient is φ = 188928.

The previous prime is 251003. The next prime is 251033. The reversal of 251005 is 500152.

It can be written as a sum of positive squares in 4 ways, for example, as 89401 + 161604 = 299^2 + 402^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 251005 - 2¹ = 251003 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1392 + ... + 1561.

It is an arithmetic number, because the mean of its divisors is an integer number (39879).

251005 is a Friedman number, since it can be written as 50201*5, using all its digits and the basic arithmetic operations.

2²⁵¹⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

251005 is a deficient number, since it is larger than the sum of its proper divisors (68027).

251005 is a wasteful number, since it uses less digits than its factorization.

251005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2975.

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 251005 is about 501.0039920001. The cubic root of 251005 is about 63.0803543413.

Adding to 251005 its reverse (500152), we get a palindrome (751157).

The spelling of 251005 in words is "two hundred fifty-one thousand, five".