245981 has 2 divisors, whose sum is σ = 245982. Its totient is φ = 245980.

The previous prime is 245977. The next prime is 245983. The reversal of 245981 is 189542.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241081 + 4900 = 491^2 + 70^2 .

It is a cyclic number.

It is not a de Polignac number, because 245981 - 2² = 245977 is a prime.

It is a super-2 number, since 2×245981² = 121013304722, which contains 22 as substring.

Together with 245983, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (245983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122990 + 122991.

It is an arithmetic number, because the mean of its divisors is an integer number (122991).

2²⁴⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

245981 is a deficient number, since it is larger than the sum of its proper divisors (1).

245981 is an equidigital number, since it uses as much as digits as its factorization.

245981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 245981 is about 495.9647164870. The cubic root of 245981 is about 62.6566523659.

The spelling of 245981 in words is "two hundred forty-five thousand, nine hundred eighty-one".