261559355856 has 40 divisors (see below), whose sum is σ = 697491619584. Its totient is φ = 84373985280.

The previous prime is 261559355851. The next prime is 261559355867. The reversal of 261559355856 is 658553955162.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 261559355856.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261559355851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87888081 + ... + 87891056.

Almost surely, 2^261559355856 is an apocalyptic number.

It is an amenable number.

261559355856 is an abundant number, since it is smaller than the sum of its proper divisors (435932263728).

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

261559355856 is a wasteful number, since it uses less digits than its factorization.

261559355856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175779179 (or 175779173 counting only the distinct ones).

The product of its digits is 48600000, while the sum is 60.

The spelling of 261559355856 in words is "two hundred sixty-one billion, five hundred fifty-nine million, three hundred fifty-five thousand, eight hundred fifty-six".