261762057256656 has 160 divisors (see below), whose sum is σ = 743133199288320. Its totient is φ = 78738328972800.

The previous prime is 261762057256577. The next prime is 261762057256663. The reversal of 261762057256656 is 656652750267162.

It is a Harshad number since it is a multiple of its sum of digits (66).

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 31 ways as a sum of consecutive naturals, for example, 55367325 + ... + 59908803.

It is an arithmetic number, because the mean of its divisors is an integer number (4644582495552).

Almost surely, 2^{261762057256656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261762057256656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (371566599644160).

261762057256656 is an abundant number, since it is smaller than the sum of its proper divisors (481371142031664).

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

261762057256656 is a wasteful number, since it uses less digits than its factorization.

261762057256656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4542305 (or 4542299 counting only the distinct ones).

The product of its (nonzero) digits is 381024000, while the sum is 66.

The spelling of 261762057256656 in words is "two hundred sixty-one trillion, seven hundred sixty-two billion, fifty-seven million, two hundred fifty-six thousand, six hundred fifty-six".