261361566 has 24 divisors (see below), whose sum is σ = 587257944. Its totient is φ = 87120360.

The previous prime is 261361487. The next prime is 261361591. The reversal of 261361566 is 665163162.

261361566 is a `hidden beast` number, since 2 + 61 + 36 + 1 + 566 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 261361566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 268405 + ... + 269376.

It is an arithmetic number, because the mean of its divisors is an integer number (24469081).

Almost surely, 2^261361566 is an apocalyptic number.

261361566 is an abundant number, since it is smaller than the sum of its proper divisors (325896378).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261361566 is an equidigital number, since it uses as much as digits as its factorization.

261361566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537798 (or 537786 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 261361566 is about 16166.6807353891. The cubic root of 261361566 is about 639.3626190188.

The spelling of 261361566 in words is "two hundred sixty-one million, three hundred sixty-one thousand, five hundred sixty-six".