872521 has 8 divisors (see below), whose sum is σ = 963144. Its totient is φ = 785280.

The previous prime is 872479. The next prime is 872533. The reversal of 872521 is 125278.

872521 = 660² + 661².

It can be written as a sum of positive squares in 4 ways, for example, as 126025 + 746496 = 355^2 + 864^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 872521 - 2⁷ = 872393 is a prime.

It is a super-2 number, since 2×872521² = 1522585790882, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

872521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (872561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 286 + ... + 1351.

It is an arithmetic number, because the mean of its divisors is an integer number (120393).

2⁸⁷²⁵²¹ is an apocalyptic number.

872521 is the 661-st centered square number.

It is an amenable number.

872521 is a deficient number, since it is larger than the sum of its proper divisors (90623).

872521 is a wasteful number, since it uses less digits than its factorization.

872521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1691.

The product of its digits is 1120, while the sum is 25.

The square root of 872521 is about 934.0883255881. The cubic root of 872521 is about 95.5561469126.

Adding to 872521 its reverse (125278), we get a palindrome (997799).

The spelling of 872521 in words is "eight hundred seventy-two thousand, five hundred twenty-one".