872016021 has 6 divisors (see below), whose sum is σ = 1259578710. Its totient is φ = 581344008.

The previous prime is 872016017. The next prime is 872016053. The reversal of 872016021 is 120610278.

It can be written as a sum of positive squares in only one way, i.e., 637007121 + 235008900 = 25239^2 + 15330^2 .

It is not a de Polignac number, because 872016021 - 2² = 872016017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (872016721) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 48445326 + ... + 48445343.

It is an arithmetic number, because the mean of its divisors is an integer number (209929785).

Almost surely, 2^872016021 is an apocalyptic number.

It is an amenable number.

872016021 is a deficient number, since it is larger than the sum of its proper divisors (387562689).

872016021 is a wasteful number, since it uses less digits than its factorization.

872016021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96890675 (or 96890672 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 872016021 is about 29529.9173889803. The cubic root of 872016021 is about 955.3770870896.

Adding to 872016021 its reverse (120610278), we get a palindrome (992626299).

The spelling of 872016021 in words is "eight hundred seventy-two million, sixteen thousand, twenty-one".