821654397 has 12 divisors (see below), whose sum is σ = 1191061404. Its totient is φ = 545818560.

The previous prime is 821654377. The next prime is 821654413. The reversal of 821654397 is 793456128.

821654397 is a `hidden beast` number, since 8 + 2 + 16 + 543 + 97 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 508682916 + 312971481 = 22554^2 + 17691^2 .

It is not a de Polignac number, because 821654397 - 2¹⁰ = 821653373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821654377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 159918 + ... + 164975.

It is an arithmetic number, because the mean of its divisors is an integer number (99255117).

Almost surely, 2^821654397 is an apocalyptic number.

It is an amenable number.

821654397 is a deficient number, since it is larger than the sum of its proper divisors (369407007).

821654397 is a wasteful number, since it uses less digits than its factorization.

821654397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325180 (or 325177 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 821654397 is about 28664.5145955762. The cubic root of 821654397 is about 936.6192107234.

The spelling of 821654397 in words is "eight hundred twenty-one million, six hundred fifty-four thousand, three hundred ninety-seven".