261220513 has 2 divisors, whose sum is σ = 261220514. Its totient is φ = 261220512.

The previous prime is 261220507. The next prime is 261220523. The reversal of 261220513 is 315022162.

261220513 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255104784 + 6115729 = 15972^2 + 2473^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261220513 is a prime.

It is not a weakly prime, because it can be changed into another prime (261220523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130610256 + 130610257.

It is an arithmetic number, because the mean of its divisors is an integer number (130610257).

Almost surely, 2^261220513 is an apocalyptic number.

It is an amenable number.

261220513 is a deficient number, since it is larger than the sum of its proper divisors (1).

261220513 is an equidigital number, since it uses as much as digits as its factorization.

261220513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 261220513 is about 16162.3176865201. The cubic root of 261220513 is about 639.2475801151.

Adding to 261220513 its reverse (315022162), we get a palindrome (576242675).

The spelling of 261220513 in words is "two hundred sixty-one million, two hundred twenty thousand, five hundred thirteen".