261691604616 has 32 divisors (see below), whose sum is σ = 704554320960. Its totient is φ = 80520493632.

The previous prime is 261691604579. The next prime is 261691604623. The reversal of 261691604616 is 616406196162.

261691604616 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 419377260 + ... + 419377883.

It is an arithmetic number, because the mean of its divisors is an integer number (22017322530).

Almost surely, 2^261691604616 is an apocalyptic number.

261691604616 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

261691604616 is an abundant number, since it is smaller than the sum of its proper divisors (442862716344).

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

261691604616 is a wasteful number, since it uses less digits than its factorization.

261691604616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838755165 (or 838755161 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 48.

The spelling of 261691604616 in words is "two hundred sixty-one billion, six hundred ninety-one million, six hundred four thousand, six hundred sixteen".