261660650285 has 4 divisors (see below), whose sum is σ = 313992780348. Its totient is φ = 209328520224.

The previous prime is 261660650263. The next prime is 261660650291. The reversal of 261660650285 is 582056066162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43465161289 + 218195488996 = 208483^2 + 467114^2 .

It is a cyclic number.

It is not a de Polignac number, because 261660650285 - 2⁶ = 261660650221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26166065024 + ... + 26166065033.

It is an arithmetic number, because the mean of its divisors is an integer number (78498195087).

Almost surely, 2^261660650285 is an apocalyptic number.

It is an amenable number.

261660650285 is a deficient number, since it is larger than the sum of its proper divisors (52332130063).

261660650285 is an equidigital number, since it uses as much as digits as its factorization.

261660650285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52332130062.

The product of its (nonzero) digits is 1036800, while the sum is 47.

The spelling of 261660650285 in words is "two hundred sixty-one billion, six hundred sixty million, six hundred fifty thousand, two hundred eighty-five".