871881665 has 24 divisors (see below), whose sum is σ = 1118554920. Its totient is φ = 651624960.

The previous prime is 871881643. The next prime is 871881667. The reversal of 871881665 is 566188178.

It can be written as a sum of positive squares in 4 ways, for example, as 341362576 + 530519089 = 18476^2 + 23033^2 .

It is not a de Polignac number, because 871881665 - 2¹² = 871877569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (871881667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136217 + ... + 142473.

It is an arithmetic number, because the mean of its divisors is an integer number (46606455).

Almost surely, 2^871881665 is an apocalyptic number.

It is an amenable number.

871881665 is a deficient number, since it is larger than the sum of its proper divisors (246673255).

871881665 is a wasteful number, since it uses less digits than its factorization.

871881665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6353 (or 6322 counting only the distinct ones).

The product of its digits is 645120, while the sum is 50.

The square root of 871881665 is about 29527.6423881081. The cubic root of 871881665 is about 955.3280179464.

The spelling of 871881665 in words is "eight hundred seventy-one million, eight hundred eighty-one thousand, six hundred sixty-five".