• 245 can be written using four 4's:

See also 113.

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245 has 6 divisors (see below), whose sum is σ = 342. Its totient is φ = 168.

The previous prime is 241. The next prime is 251. The reversal of 245 is 542.

245 = 8² + 9² + 10².

It can be written as a sum of positive squares in only one way, i.e., 196 + 49 = 14^2 + 7^2 .

It is not a de Polignac number, because 245 - 2² = 241 is a prime.

It is a magnanimous number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 10, base 13, base 14 and base 15.

It is a nialpdrome in base 4, base 7 and base 16.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (241) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 32 + ... + 38.

It is an arithmetic number, because the mean of its divisors is an integer number (57).

2²⁴⁵ is an apocalyptic number.

It is an amenable number.

245 is a deficient number, since it is larger than the sum of its proper divisors (97).

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

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

The sum of its prime factors is 19 (or 12 counting only the distinct ones).

The product of its digits is 40, while the sum is 11.

The square root of 245 is about 15.6524758425. The cubic root of 245 is about 6.2573247457.

Adding to 245 its sum of digits (11), we get a 8-th power (256 = 2⁸).

Adding to 245 its reverse (542), we get a palindrome (787).

It can be divided in two parts, 24 and 5, that multiplied together give a triangular number (120 = T₁₅).

The spelling of 245 in words is "two hundred forty-five", and thus it is an aban number.