820939687 has 2 divisors, whose sum is σ = 820939688. Its totient is φ = 820939686.

The previous prime is 820939681. The next prime is 820939697. The reversal of 820939687 is 786939028.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820939687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820939681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410469843 + 410469844.

It is an arithmetic number, because the mean of its divisors is an integer number (410469844).

Almost surely, 2^820939687 is an apocalyptic number.

820939687 is a deficient number, since it is larger than the sum of its proper divisors (1).

820939687 is an equidigital number, since it uses as much as digits as its factorization.

820939687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 52.

The square root of 820939687 is about 28652.0450753520. The cubic root of 820939687 is about 936.3475615132.

The spelling of 820939687 in words is "eight hundred twenty million, nine hundred thirty-nine thousand, six hundred eighty-seven".