865778870477061 has 40 divisors (see below), whose sum is σ = 1315260414980160. Its totient is φ = 567396338142528.

The previous prime is 865778870477041. The next prime is 865778870477077. The reversal of 865778870477061 is 160774078877568.

865778870477061 is a `hidden beast` number, since 8 + 6 + 5 + 7 + 7 + 8 + 87 + 0 + 477 + 0 + 61 = 666.

It is not a de Polignac number, because 865778870477061 - 2¹⁸ = 865778870214917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865778870477041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 416806296 + ... + 418878318.

It is an arithmetic number, because the mean of its divisors is an integer number (32881510374504).

Almost surely, 2^{865778870477061} is an apocalyptic number.

865778870477061 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

865778870477061 is a deficient number, since it is larger than the sum of its proper divisors (449481544503099).

865778870477061 is a wasteful number, since it uses less digits than its factorization.

865778870477061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2159527 (or 2159518 counting only the distinct ones).

The product of its (nonzero) digits is 6195732480, while the sum is 81.

The spelling of 865778870477061 in words is "eight hundred sixty-five trillion, seven hundred seventy-eight billion, eight hundred seventy million, four hundred seventy-seven thousand, sixty-one".