821478 has 16 divisors (see below), whose sum is σ = 1877760. Its totient is φ = 234696.

The previous prime is 821477. The next prime is 821479. The reversal of 821478 is 874128.

It is an interprime number because it is at equal distance from previous prime (821477) and next prime (821479).

It is a super-2 number, since 2×821478² = 1349652208968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821477) 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, 9738 + ... + 9821.

It is an arithmetic number, because the mean of its divisors is an integer number (117360).

2⁸²¹⁴⁷⁸ is an apocalyptic number.

821478 is an abundant number, since it is smaller than the sum of its proper divisors (1056282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821478 is a wasteful number, since it uses less digits than its factorization.

821478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19571.

The product of its digits is 3584, while the sum is 30.

The square root of 821478 is about 906.3542353848. The cubic root of 821478 is about 93.6552179847.

Subtracting 821478 from its reverse (874128), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 821478 in words is "eight hundred twenty-one thousand, four hundred seventy-eight".