821673386228816 has 20 divisors (see below), whose sum is σ = 1736718748165824. Its totient is φ = 373487902831200.

The previous prime is 821673386228803. The next prime is 821673386228831. The reversal of 821673386228816 is 618822683376128.

It is a self number, because there is not a number n which added to its sum of digits gives 821673386228816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2334299392520 + ... + 2334299392871.

Almost surely, 2^{821673386228816} is an apocalyptic number.

It is an amenable number.

821673386228816 is an abundant number, since it is smaller than the sum of its proper divisors (915045361937008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821673386228816 is a wasteful number, since it uses less digits than its factorization.

821673386228816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4668598785410 (or 4668598785404 counting only the distinct ones).

The product of its digits is 445906944, while the sum is 71.

The spelling of 821673386228816 in words is "eight hundred twenty-one trillion, six hundred seventy-three billion, three hundred eighty-six million, two hundred twenty-eight thousand, eight hundred sixteen".