821804913 has 8 divisors (see below), whose sum is σ = 1217488800. Its totient is φ = 547869924.

The previous prime is 821804903. The next prime is 821804933. The reversal of 821804913 is 319408128.

It is not a de Polignac number, because 821804913 - 2⁴ = 821804897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821804903) 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, 15218583 + ... + 15218636.

It is an arithmetic number, because the mean of its divisors is an integer number (152186100).

Almost surely, 2^821804913 is an apocalyptic number.

It is an amenable number.

821804913 is a deficient number, since it is larger than the sum of its proper divisors (395683887).

821804913 is a wasteful number, since it uses less digits than its factorization.

821804913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30437228 (or 30437222 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 821804913 is about 28667.1399515194. The cubic root of 821804913 is about 936.6763992324.

The spelling of 821804913 in words is "eight hundred twenty-one million, eight hundred four thousand, nine hundred thirteen".