821404 has 12 divisors (see below), whose sum is σ = 1446984. Its totient is φ = 407984.

The previous prime is 821383. The next prime is 821411. The reversal of 821404 is 404128.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99 + ... + 1285.

It is an arithmetic number, because the mean of its divisors is an integer number (120582).

2⁸²¹⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

821404 is a deficient number, since it is larger than the sum of its proper divisors (625580).

821404 is a wasteful number, since it uses less digits than its factorization.

821404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364 (or 1362 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 821404 is about 906.3134115746. The cubic root of 821404 is about 93.6524056983.

It can be divided in two parts, 821 and 404, that added together give a triangular number (1225 = T₄₉).

The spelling of 821404 in words is "eight hundred twenty-one thousand, four hundred four".