261626569 has 2 divisors, whose sum is σ = 261626570. Its totient is φ = 261626568.

The previous prime is 261626539. The next prime is 261626609. The reversal of 261626569 is 965626162.

261626569 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., 173923344 + 87703225 = 13188^2 + 9365^2 .

It is a cyclic number.

It is not a de Polignac number, because 261626569 - 2⁵ = 261626537 is a prime.

It is a super-2 number, since 2×261626569² = 136896923213423522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261626539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130813284 + 130813285.

It is an arithmetic number, because the mean of its divisors is an integer number (130813285).

Almost surely, 2^261626569 is an apocalyptic number.

It is an amenable number.

261626569 is a deficient number, since it is larger than the sum of its proper divisors (1).

261626569 is an equidigital number, since it uses as much as digits as its factorization.

261626569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 43.

The square root of 261626569 is about 16174.8746208433. The cubic root of 261626569 is about 639.5786362172.

The spelling of 261626569 in words is "two hundred sixty-one million, six hundred twenty-six thousand, five hundred sixty-nine".