821723888813 has 16 divisors (see below), whose sum is σ = 869507654400. Its totient is φ = 774400515840.

The previous prime is 821723888779. The next prime is 821723888849. The reversal of 821723888813 is 318888327128.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 821723888813 - 2³⁰ = 820650146989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821723888863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4232633 + ... + 4422513.

It is an arithmetic number, because the mean of its divisors is an integer number (54344228400).

Almost surely, 2^821723888813 is an apocalyptic number.

It is an amenable number.

821723888813 is a deficient number, since it is larger than the sum of its proper divisors (47783765587).

821723888813 is a wasteful number, since it uses less digits than its factorization.

821723888813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191092.

The product of its digits is 8257536, while the sum is 59.

The spelling of 821723888813 in words is "eight hundred twenty-one billion, seven hundred twenty-three million, eight hundred eighty-eight thousand, eight hundred thirteen".