84871021 has 4 divisors (see below), whose sum is σ = 89863452. Its totient is φ = 79878592.

The previous prime is 84871019. The next prime is 84871079. The reversal of 84871021 is 12017848.

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 52722121 + 32148900 = 7261^2 + 5670^2 .

It is a cyclic number.

It is not a de Polignac number, because 84871021 - 2¹ = 84871019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84871001) 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, 2496190 + ... + 2496223.

It is an arithmetic number, because the mean of its divisors is an integer number (22465863).

Almost surely, 2^84871021 is an apocalyptic number.

It is an amenable number.

84871021 is a deficient number, since it is larger than the sum of its proper divisors (4992431).

84871021 is a wasteful number, since it uses less digits than its factorization.

84871021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4992430.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 84871021 is about 9212.5469333947. The cubic root of 84871021 is about 439.4604629904.

Adding to 84871021 its reverse (12017848), we get a palindrome (96888869).

The spelling of 84871021 in words is "eighty-four million, eight hundred seventy-one thousand, twenty-one".