261335255640 has 64 divisors (see below), whose sum is σ = 798798348000. Its totient is φ = 68374505472.

The previous prime is 261335255617. The next prime is 261335255663. The reversal of 261335255640 is 46552533162.

It is a happy number.

261335255640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261335255617) and next prime (261335255663).

It is a super-2 number, since 2×261335255640² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261335255592 and 261335255601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20538865 + ... + 20551584.

Almost surely, 2^261335255640 is an apocalyptic number.

261335255640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261335255640 is an abundant number, since it is smaller than the sum of its proper divisors (537463092360).

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

261335255640 is a wasteful number, since it uses less digits than its factorization.

261335255640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41090516 (or 41090512 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 42.

The spelling of 261335255640 in words is "two hundred sixty-one billion, three hundred thirty-five million, two hundred fifty-five thousand, six hundred forty".