261553251266678 has 12 divisors (see below), whose sum is σ = 456383734353252. Its totient is φ = 112094250542820.

The previous prime is 261553251266621. The next prime is 261553251266687. The reversal of 261553251266678 is 876662152355162.

It is a super-2 number, since 2×261553251266678² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1334455363508 + ... + 1334455363703.

It is an arithmetic number, because the mean of its divisors is an integer number (38031977862771).

Almost surely, 2^{261553251266678} is an apocalyptic number.

261553251266678 is a deficient number, since it is larger than the sum of its proper divisors (194830483086574).

261553251266678 is a wasteful number, since it uses less digits than its factorization.

261553251266678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668910727227 (or 2668910727220 counting only the distinct ones).

The product of its digits is 217728000, while the sum is 65.

The spelling of 261553251266678 in words is "two hundred sixty-one trillion, five hundred fifty-three billion, two hundred fifty-one million, two hundred sixty-six thousand, six hundred seventy-eight".