821248665 has 32 divisors (see below), whose sum is σ = 1393894656. Its totient is φ = 411463680.

The previous prime is 821248601. The next prime is 821248669. The reversal of 821248665 is 566842128.

It is not a de Polignac number, because 821248665 - 2⁶ = 821248601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821248669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 148500 + ... + 153930.

It is an arithmetic number, because the mean of its divisors is an integer number (43559208).

Almost surely, 2^821248665 is an apocalyptic number.

821248665 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

821248665 is a deficient number, since it is larger than the sum of its proper divisors (572645991).

821248665 is a wasteful number, since it uses less digits than its factorization.

821248665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6049.

The product of its digits is 184320, while the sum is 42.

The square root of 821248665 is about 28657.4364694402. The cubic root of 821248665 is about 936.4650181762.

The spelling of 821248665 in words is "eight hundred twenty-one million, two hundred forty-eight thousand, six hundred sixty-five".