870521 has 4 divisors (see below), whose sum is σ = 872592. Its totient is φ = 868452.

The previous prime is 870517. The next prime is 870533. The reversal of 870521 is 125078.

870521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 125078 = 2 ⋅62539.

It is a cyclic number.

It is not a de Polignac number, because 870521 - 2² = 870517 is a prime.

It is a super-2 number, since 2×870521² = 1515613622882, which contains 22 as substring.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (875521) 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, 155 + ... + 1328.

It is an arithmetic number, because the mean of its divisors is an integer number (218148).

2⁸⁷⁰⁵²¹ is an apocalyptic number.

It is an amenable number.

870521 is a deficient number, since it is larger than the sum of its proper divisors (2071).

870521 is a wasteful number, since it uses less digits than its factorization.

870521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2070.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 870521 is about 933.0171488242. The cubic root of 870521 is about 95.4830795201.

Adding to 870521 its reverse (125078), we get a palindrome (995599).

The spelling of 870521 in words is "eight hundred seventy thousand, five hundred twenty-one".