821345887 has 2 divisors, whose sum is σ = 821345888. Its totient is φ = 821345886.

The previous prime is 821345809. The next prime is 821345897. The reversal of 821345887 is 788543128.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 821345887 - 2²³ = 812957279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821345897) 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 as a sum of consecutive naturals, namely, 410672943 + 410672944.

It is an arithmetic number, because the mean of its divisors is an integer number (410672944).

Almost surely, 2^821345887 is an apocalyptic number.

821345887 is a deficient number, since it is larger than the sum of its proper divisors (1).

821345887 is an equidigital number, since it uses as much as digits as its factorization.

821345887 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 430080, while the sum is 46.

The square root of 821345887 is about 28659.1326979726. The cubic root of 821345887 is about 936.5019706094.

The spelling of 821345887 in words is "eight hundred twenty-one million, three hundred forty-five thousand, eight hundred eighty-seven".