261161651661604 has 24 divisors (see below), whose sum is σ = 467737029986688. Its totient is φ = 127523480337120.

The previous prime is 261161651661509. The next prime is 261161651661611. The reversal of 261161651661604 is 406166156161162.

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, 121443532 + ... + 123575299.

It is an arithmetic number, because the mean of its divisors is an integer number (19489042916112).

Almost surely, 2^{261161651661604} is an apocalyptic number.

It is an amenable number.

261161651661604 is a deficient number, since it is larger than the sum of its proper divisors (206575378325084).

261161651661604 is a wasteful number, since it uses less digits than its factorization.

261161651661604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245025075 (or 245025073 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 52.

The spelling of 261161651661604 in words is "two hundred sixty-one trillion, one hundred sixty-one billion, six hundred fifty-one million, six hundred sixty-one thousand, six hundred four".