821023087979 has 4 divisors (see below), whose sum is σ = 821027654784. Its totient is φ = 821018521176.

The previous prime is 821023087967. The next prime is 821023087991. The reversal of 821023087979 is 979780320128.

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

It is an interprime number because it is at equal distance from previous prime (821023087967) and next prime (821023087991).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821023087979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821023087879) 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, 2002187 + ... + 2377140.

It is an arithmetic number, because the mean of its divisors is an integer number (205256913696).

Almost surely, 2^821023087979 is an apocalyptic number.

821023087979 is a deficient number, since it is larger than the sum of its proper divisors (4566805).

821023087979 is a wasteful number, since it uses less digits than its factorization.

821023087979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4566804.

The product of its (nonzero) digits is 3048192, while the sum is 56.

The spelling of 821023087979 in words is "eight hundred twenty-one billion, twenty-three million, eighty-seven thousand, nine hundred seventy-nine".