821943387 has 48 divisors (see below), whose sum is σ = 1322500608. Its totient is φ = 489265920.

The previous prime is 821943383. The next prime is 821943389. The reversal of 821943387 is 783349128.

821943387 is a `hidden beast` number, since 82 + 194 + 3 + 387 = 666.

It is not a de Polignac number, because 821943387 - 2² = 821943383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821943383) 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 47 ways as a sum of consecutive naturals, for example, 460098 + ... + 461880.

It is an arithmetic number, because the mean of its divisors is an integer number (27552096).

Almost surely, 2^821943387 is an apocalyptic number.

821943387 is a deficient number, since it is larger than the sum of its proper divisors (500557221).

821943387 is a wasteful number, since it uses less digits than its factorization.

821943387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1960 (or 1957 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 821943387 is about 28669.5550540988. Note that the first 3 decimals coincide. The cubic root of 821943387 is about 936.7290062203.

The spelling of 821943387 in words is "eight hundred twenty-one million, nine hundred forty-three thousand, three hundred eighty-seven".