261789815716 has 81 divisors (see below), whose sum is σ = 545587332003. Its totient is φ = 109780482240.

The previous prime is 261789815699. The next prime is 261789815731. The reversal of 261789815716 is 617518987162.

The square root of 261789815716 is 511654.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 6465768100 + 255324047616 = 80410^2 + 505296^2 .

It is a super-2 number, since 2×261789815716² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 146332150 + ... + 146333938.

Almost surely, 2^261789815716 is an apocalyptic number.

261789815716 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

261789815716 is the 511654-th square number.

It is an amenable number.

261789815716 is an abundant number, since it is smaller than the sum of its proper divisors (283797516287).

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

261789815716 is a wasteful number, since it uses less digits than its factorization.

261789815716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3630 (or 1815 counting only the distinct ones).

The product of its digits is 10160640, while the sum is 61.

The spelling of 261789815716 in words is "two hundred sixty-one billion, seven hundred eighty-nine million, eight hundred fifteen thousand, seven hundred sixteen".