261569513857 has 16 divisors (see below), whose sum is σ = 275523955200. Its totient is φ = 247839400512.

The previous prime is 261569513851. The next prime is 261569513969. The reversal of 261569513857 is 758315965162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261569513857 - 2¹⁹ = 261568989569 is a prime.

It is a super-2 number, since 2×261569513857² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261569513851) 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, 1153723 + ... + 1361695.

It is an arithmetic number, because the mean of its divisors is an integer number (17220247200).

Almost surely, 2^261569513857 is an apocalyptic number.

It is an amenable number.

261569513857 is a deficient number, since it is larger than the sum of its proper divisors (13954441343).

261569513857 is a wasteful number, since it uses less digits than its factorization.

261569513857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208512.

The product of its digits is 13608000, while the sum is 58.

The spelling of 261569513857 in words is "two hundred sixty-one billion, five hundred sixty-nine million, five hundred thirteen thousand, eight hundred fifty-seven".