821001023 has 4 divisors (see below), whose sum is σ = 829129848. Its totient is φ = 812872200.

The previous prime is 821001019. The next prime is 821001053. The reversal of 821001023 is 320100128.

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 821001023 - 2² = 821001019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 821000992 and 821001010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821001053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4064261 + ... + 4064462.

It is an arithmetic number, because the mean of its divisors is an integer number (207282462).

Almost surely, 2^821001023 is an apocalyptic number.

821001023 is a deficient number, since it is larger than the sum of its proper divisors (8128825).

821001023 is a wasteful number, since it uses less digits than its factorization.

821001023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8128824.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 821001023 is about 28653.1154152563. The cubic root of 821001023 is about 936.3708804751.

The spelling of 821001023 in words is "eight hundred twenty-one million, one thousand, twenty-three".