261906665852160 has 864 divisors, whose sum is σ = 1105062807663360. Its totient is φ = 55936701038592.

The previous prime is 261906665852093. The next prime is 261906665852173. The reversal of 261906665852160 is 61258566609162.

It is a hoax number, since the sum of its digits (63) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 110676862 + ... + 113018498.

It is an arithmetic number, because the mean of its divisors is an integer number (1279007879240).

Almost surely, 2^{261906665852160} is an apocalyptic number.

261906665852160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261906665852160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (552531403831680).

261906665852160 is an abundant number, since it is smaller than the sum of its proper divisors (843156141811200).

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

261906665852160 is a wasteful number, since it uses less digits than its factorization.

261906665852160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2341763 (or 2341746 counting only the distinct ones).

The product of its (nonzero) digits is 55987200, while the sum is 63.

The spelling of 261906665852160 in words is "two hundred sixty-one trillion, nine hundred six billion, six hundred sixty-five million, eight hundred fifty-two thousand, one hundred sixty".