261520376640 has 112 divisors (see below), whose sum is σ = 833391962880. Its totient is φ = 69481359360.

The previous prime is 261520376633. The next prime is 261520376659. The reversal of 261520376640 is 46673025162.

It is a junction number, because it is equal to n+sod(n) for n = 261520376592 and 261520376601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 242455 + ... + 762774.

Almost surely, 2^261520376640 is an apocalyptic number.

261520376640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261520376640 is an abundant number, since it is smaller than the sum of its proper divisors (571871586240).

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

261520376640 is a wasteful number, since it uses less digits than its factorization.

261520376640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005520 (or 1005510 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 42.

The spelling of 261520376640 in words is "two hundred sixty-one billion, five hundred twenty million, three hundred seventy-six thousand, six hundred forty".