821404233 has 20 divisors (see below), whose sum is σ = 1321425028. Its totient is φ = 505478880.

The previous prime is 821404217. The next prime is 821404247. The reversal of 821404233 is 332404128.

821404233 is a `hidden beast` number, since 8 + 21 + 404 + 233 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 34433424 + 786970809 = 5868^2 + 28053^2 .

It is not a de Polignac number, because 821404233 - 2⁴ = 821404217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 821404197 and 821404206.

It is not an unprimeable number, because it can be changed into a prime (821404253) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 388978 + ... + 391083.

Almost surely, 2^821404233 is an apocalyptic number.

It is an amenable number.

821404233 is a deficient number, since it is larger than the sum of its proper divisors (500020795).

821404233 is a wasteful number, since it uses less digits than its factorization.

821404233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780086 (or 780077 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 821404233 is about 28660.1506102114. The cubic root of 821404233 is about 936.5241455344.

The spelling of 821404233 in words is "eight hundred twenty-one million, four hundred four thousand, two hundred thirty-three".