821505995 has 4 divisors (see below), whose sum is σ = 985807200. Its totient is φ = 657204792.

The previous prime is 821505991. The next prime is 821506031. The reversal of 821505995 is 599505128.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 821505995 - 2² = 821505991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821505991) 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 3 ways as a sum of consecutive naturals, for example, 82150595 + ... + 82150604.

It is an arithmetic number, because the mean of its divisors is an integer number (246451800).

Almost surely, 2^821505995 is an apocalyptic number.

821505995 is a deficient number, since it is larger than the sum of its proper divisors (164301205).

821505995 is a wasteful number, since it uses less digits than its factorization.

821505995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164301204.

The product of its (nonzero) digits is 162000, while the sum is 44.

The square root of 821505995 is about 28661.9258773726. The cubic root of 821505995 is about 936.5628185900.

The spelling of 821505995 in words is "eight hundred twenty-one million, five hundred five thousand, nine hundred ninety-five".