821506850985 has 16 divisors (see below), whose sum is σ = 1316204172864. Its totient is φ = 437539250112.

The previous prime is 821506850971. The next prime is 821506850993. The reversal of 821506850985 is 589058605128.

It is not a de Polignac number, because 821506850985 - 2¹⁸ = 821506588841 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37347207 + ... + 37369196.

It is an arithmetic number, because the mean of its divisors is an integer number (82262760804).

Almost surely, 2^821506850985 is an apocalyptic number.

It is an amenable number.

821506850985 is a deficient number, since it is larger than the sum of its proper divisors (494697321879).

821506850985 is a wasteful number, since it uses less digits than its factorization.

821506850985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74717144.

The product of its (nonzero) digits is 6912000, while the sum is 57.

The spelling of 821506850985 in words is "eight hundred twenty-one billion, five hundred six million, eight hundred fifty thousand, nine hundred eighty-five".