245521 has 2 divisors, whose sum is σ = 245522. Its totient is φ = 245520.

The previous prime is 245519. The next prime is 245527. The reversal of 245521 is 125542.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 239121 + 6400 = 489^2 + 80^2 .

It is a cyclic number.

It is not a de Polignac number, because 245521 - 2¹ = 245519 is a prime.

It is a super-2 number, since 2×245521² = 120561122882, which contains 22 as substring.

Together with 245519, it forms a pair of twin primes.

It is the 496-th Hogben number.

It is equal to p₂₁₆₇₃ and since 245521 and 21673 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (245527) by changing a digit.

It is a nontrivial repunit in base 495.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122760 + 122761.

It is an arithmetic number, because the mean of its divisors is an integer number (122761).

2²⁴⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

245521 is a deficient number, since it is larger than the sum of its proper divisors (1).

245521 is an equidigital number, since it uses as much as digits as its factorization.

245521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 400, while the sum is 19.

The square root of 245521 is about 495.5007568107. The cubic root of 245521 is about 62.6175706954.

The spelling of 245521 in words is "two hundred forty-five thousand, five hundred twenty-one".