245811 has 4 divisors (see below), whose sum is σ = 327752. Its totient is φ = 163872.

The previous prime is 245789. The next prime is 245821. The reversal of 245811 is 118542.

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

It is not a de Polignac number, because 245811 - 2⁶ = 245747 is a prime.

It is a D-number.

It is a Duffinian number.

245811 is a lucky number.

It is a zygodrome in base 2.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 245811.

It is not an unprimeable number, because it can be changed into a prime (245821) 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, 40966 + ... + 40971.

It is an arithmetic number, because the mean of its divisors is an integer number (81938).

2²⁴⁵⁸¹¹ is an apocalyptic number.

245811 is a deficient number, since it is larger than the sum of its proper divisors (81941).

245811 is an equidigital number, since it uses as much as digits as its factorization.

245811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81940.

The product of its digits is 320, while the sum is 21.

The square root of 245811 is about 495.7933037063. The cubic root of 245811 is about 62.6422148203.

The spelling of 245811 in words is "two hundred forty-five thousand, eight hundred eleven".