261335620609 has 16 divisors (see below), whose sum is σ = 301637670400. Its totient is φ = 221778782784.

The previous prime is 261335620549. The next prime is 261335620613. The reversal of 261335620609 is 906026533162.

It is a cyclic number.

It is not a de Polignac number, because 261335620609 - 2³⁷ = 123896667137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261335620409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 883447 + ... + 1141555.

It is an arithmetic number, because the mean of its divisors is an integer number (18852354400).

Almost surely, 2^261335620609 is an apocalyptic number.

It is an amenable number.

261335620609 is a deficient number, since it is larger than the sum of its proper divisors (40302049791).

261335620609 is a wasteful number, since it uses less digits than its factorization.

261335620609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259552.

The product of its (nonzero) digits is 349920, while the sum is 43.

The spelling of 261335620609 in words is "two hundred sixty-one billion, three hundred thirty-five million, six hundred twenty thousand, six hundred nine".