261488728312877 has 24 divisors (see below), whose sum is σ = 292444938379944. Its totient is φ = 233575870454784.

The previous prime is 261488728312873. The next prime is 261488728312883. The reversal of 261488728312877 is 778213827884162.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 176604457926121 + 84884270386756 = 13289261^2 + 9213266^2 .

It is not a de Polignac number, because 261488728312877 - 2² = 261488728312873 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261488728312871) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 199303568 + ... + 200611289.

It is an arithmetic number, because the mean of its divisors is an integer number (12185205765831).

Almost surely, 2^{261488728312877} is an apocalyptic number.

It is an amenable number.

261488728312877 is a deficient number, since it is larger than the sum of its proper divisors (30956210067067).

261488728312877 is a wasteful number, since it uses less digits than its factorization.

261488728312877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399915009 (or 399914996 counting only the distinct ones).

The product of its digits is 809238528, while the sum is 74.

The spelling of 261488728312877 in words is "two hundred sixty-one trillion, four hundred eighty-eight billion, seven hundred twenty-eight million, three hundred twelve thousand, eight hundred seventy-seven".