865221507865 has 32 divisors (see below), whose sum is σ = 1221038001792. Its totient is φ = 580249344000.

The previous prime is 865221507863. The next prime is 865221507869. The reversal of 865221507865 is 568705122568.

It is not a de Polignac number, because 865221507865 - 2¹ = 865221507863 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (865221507863) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 71145 + ... + 1317385.

It is an arithmetic number, because the mean of its divisors is an integer number (38157437556).

Almost surely, 2^865221507865 is an apocalyptic number.

It is an amenable number.

865221507865 is a deficient number, since it is larger than the sum of its proper divisors (355816493927).

865221507865 is a wasteful number, since it uses less digits than its factorization.

865221507865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247241.

The product of its (nonzero) digits is 8064000, while the sum is 55.

The spelling of 865221507865 in words is "eight hundred sixty-five billion, two hundred twenty-one million, five hundred seven thousand, eight hundred sixty-five".