871521905 has 4 divisors (see below), whose sum is σ = 1045826292. Its totient is φ = 697217520.

The previous prime is 871521869. The next prime is 871521907. The reversal of 871521905 is 509125178.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 302794801 + 568727104 = 17401^2 + 23848^2 .

It is not a de Polignac number, because 871521905 - 2⁸ = 871521649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (871521907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87152186 + ... + 87152195.

It is an arithmetic number, because the mean of its divisors is an integer number (261456573).

Almost surely, 2^871521905 is an apocalyptic number.

It is an amenable number.

871521905 is a deficient number, since it is larger than the sum of its proper divisors (174304387).

871521905 is a wasteful number, since it uses less digits than its factorization.

871521905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174304386.

The product of its (nonzero) digits is 25200, while the sum is 38.

The square root of 871521905 is about 29521.5498407519. The cubic root of 871521905 is about 955.1966025247.

The spelling of 871521905 in words is "eight hundred seventy-one million, five hundred twenty-one thousand, nine hundred five".