261655567 has 12 divisors (see below), whose sum is σ = 274314544. Its totient is φ = 249559200.

The previous prime is 261655561. The next prime is 261655571. The reversal of 261655567 is 765556162.

261655567 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261655567 - 2²⁷ = 127437839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261655561) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 317518 + ... + 318340.

Almost surely, 2^261655567 is an apocalyptic number.

261655567 is a deficient number, since it is larger than the sum of its proper divisors (12658977).

261655567 is an equidigital number, since it uses as much as digits as its factorization.

261655567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1470 (or 1447 counting only the distinct ones).

The product of its digits is 378000, while the sum is 43.

The square root of 261655567 is about 16175.7709862621. The cubic root of 261655567 is about 639.6022650816.

The spelling of 261655567 in words is "two hundred sixty-one million, six hundred fifty-five thousand, five hundred sixty-seven".