261190566 has 48 divisors (see below), whose sum is σ = 696512544. Its totient is φ = 68884992.

The previous prime is 261190529. The next prime is 261190577. The reversal of 261190566 is 665091162.

261190566 is a `hidden beast` number, since 2 + 6 + 1 + 1 + 90 + 566 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 261190566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 78091 + ... + 81366.

It is an arithmetic number, because the mean of its divisors is an integer number (14510678).

Almost surely, 2^261190566 is an apocalyptic number.

261190566 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

261190566 is an abundant number, since it is smaller than the sum of its proper divisors (435321978).

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

261190566 is a wasteful number, since it uses less digits than its factorization.

261190566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159485 (or 159482 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 261190566 is about 16161.3912148676. The cubic root of 261190566 is about 639.2231508457.

The spelling of 261190566 in words is "two hundred sixty-one million, one hundred ninety thousand, five hundred sixty-six".