870421 has 4 divisors (see below), whose sum is σ = 880992. Its totient is φ = 859852.

The previous prime is 870413. The next prime is 870431. The reversal of 870421 is 124078.

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: 124078 = 2 ⋅62039.

It is a cyclic number.

It is not a de Polignac number, because 870421 - 2³ = 870413 is a prime.

It is a Duffinian number.

870421 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 870392 and 870401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (870431) 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, 5161 + ... + 5326.

It is an arithmetic number, because the mean of its divisors is an integer number (220248).

2⁸⁷⁰⁴²¹ is an apocalyptic number.

It is an amenable number.

870421 is a deficient number, since it is larger than the sum of its proper divisors (10571).

870421 is a wasteful number, since it uses less digits than its factorization.

870421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10570.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 870421 is about 932.9635577020. The cubic root of 870421 is about 95.4794232140.

Adding to 870421 its reverse (124078), we get a palindrome (994499).

The spelling of 870421 in words is "eight hundred seventy thousand, four hundred twenty-one".