261666374641420 has 48 divisors (see below), whose sum is σ = 629748600929280. Its totient is φ = 89464285335744.

The previous prime is 261666374641391. The next prime is 261666374641433. The reversal of 261666374641420 is 24146473666162.

It is a super-3 number, since 3×261666374641420³ (a number of 44 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2603077224 + ... + 2603177743.

It is an arithmetic number, because the mean of its divisors is an integer number (13119762519360).

Almost surely, 2^{261666374641420} is an apocalyptic number.

261666374641420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261666374641420 is an abundant number, since it is smaller than the sum of its proper divisors (368082226287860).

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

261666374641420 is a wasteful number, since it uses less digits than its factorization.

261666374641420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5206255342 (or 5206255340 counting only the distinct ones).

The product of its (nonzero) digits is 41803776, while the sum is 58.

The spelling of 261666374641420 in words is "two hundred sixty-one trillion, six hundred sixty-six billion, three hundred seventy-four million, six hundred forty-one thousand, four hundred twenty".