261766251620 has 12 divisors (see below), whose sum is σ = 549709128444. Its totient is φ = 104706500640.

The previous prime is 261766251581. The next prime is 261766251631. The reversal of 261766251620 is 26152667162.

It can be written as a sum of positive squares in 2 ways, for example, as 41474951716 + 220291299904 = 203654^2 + 469352^2 .

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, 6544156271 + ... + 6544156310.

It is an arithmetic number, because the mean of its divisors is an integer number (45809094037).

Almost surely, 2^261766251620 is an apocalyptic number.

261766251620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261766251620 is an abundant number, since it is smaller than the sum of its proper divisors (287942876824).

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

261766251620 is a wasteful number, since it uses less digits than its factorization.

261766251620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13088312590 (or 13088312588 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 44.

The spelling of 261766251620 in words is "two hundred sixty-one billion, seven hundred sixty-six million, two hundred fifty-one thousand, six hundred twenty".