261665113074420 has 96 divisors (see below), whose sum is σ = 799270751010816. Its totient is φ = 63433747024000.

The previous prime is 261665113074419. The next prime is 261665113074433. The reversal of 261665113074420 is 24470311566162.

It is a self number, because there is not a number n which added to its sum of digits gives 261665113074420.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 271760845 + ... + 272721995.

It is an arithmetic number, because the mean of its divisors is an integer number (8325736989696).

Almost surely, 2^{261665113074420} is an apocalyptic number.

261665113074420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261665113074420 is an abundant number, since it is smaller than the sum of its proper divisors (537605637936396).

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

261665113074420 is a wasteful number, since it uses less digits than its factorization.

261665113074420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373661 (or 1373659 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 48.

The spelling of 261665113074420 in words is "two hundred sixty-one trillion, six hundred sixty-five billion, one hundred thirteen million, seventy-four thousand, four hundred twenty".