261665001633366 has 12 divisors (see below), whose sum is σ = 566940836872332. Its totient is φ = 87221667211116.

The previous prime is 261665001633341. The next prime is 261665001633367. The reversal of 261665001633366 is 663336100566162.

261665001633366 is a `hidden beast` number, since 2 + 6 + 1 + 66 + 500 + 16 + 3 + 3 + 3 + 66 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261665001633367) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7268472267576 + ... + 7268472267611.

It is an arithmetic number, because the mean of its divisors is an integer number (47245069739361).

Almost surely, 2^{261665001633366} is an apocalyptic number.

261665001633366 is an abundant number, since it is smaller than the sum of its proper divisors (305275835238966).

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

261665001633366 is a wasteful number, since it uses less digits than its factorization.

261665001633366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14536944535195 (or 14536944535192 counting only the distinct ones).

The product of its (nonzero) digits is 12597120, while the sum is 54.

The spelling of 261665001633366 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, one million, six hundred thirty-three thousand, three hundred sixty-six".