251641 has 6 divisors (see below), whose sum is σ = 272670. Its totient is φ = 232128.

The previous prime is 251639. The next prime is 251653. The reversal of 251641 is 146152.

It can be written as a sum of positive squares in 3 ways, for example, as 5625 + 246016 = 75^2 + 496^2 .

It is not a de Polignac number, because 251641 - 2¹ = 251639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 576 + ... + 913.

It is an arithmetic number, because the mean of its divisors is an integer number (45445).

2²⁵¹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

251641 is a deficient number, since it is larger than the sum of its proper divisors (21029).

251641 is a wasteful number, since it uses less digits than its factorization.

251641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515 (or 1502 counting only the distinct ones).

The product of its digits is 240, while the sum is 19.

The square root of 251641 is about 501.6383159209. The cubic root of 251641 is about 63.1335873688.

Adding to 251641 its reverse (146152), we get a palindrome (397793).

The spelling of 251641 in words is "two hundred fifty-one thousand, six hundred forty-one".