261252166485278 has 32 divisors (see below), whose sum is σ = 440068216956480. Its totient is φ = 115669065346560.

The previous prime is 261252166485269. The next prime is 261252166485287. The reversal of 261252166485278 is 872584661252162.

It is an interprime number because it is at equal distance from previous prime (261252166485269) and next prime (261252166485287).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2738329793 + ... + 2738425196.

It is an arithmetic number, because the mean of its divisors is an integer number (13752131779890).

Almost surely, 2^{261252166485278} is an apocalyptic number.

261252166485278 is a deficient number, since it is larger than the sum of its proper divisors (178816050471202).

261252166485278 is a wasteful number, since it uses less digits than its factorization.

261252166485278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5476755092.

The product of its digits is 154828800, while the sum is 65.

The spelling of 261252166485278 in words is "two hundred sixty-one trillion, two hundred fifty-two billion, one hundred sixty-six million, four hundred eighty-five thousand, two hundred seventy-eight".