821701994523 has 16 divisors (see below), whose sum is σ = 1096817863680. Its totient is φ = 547193909664.

The previous prime is 821701994459. The next prime is 821701994569. The reversal of 821701994523 is 325499107128.

It is not a de Polignac number, because 821701994523 - 2⁶ = 821701994459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821701994423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21798390 + ... + 21836052.

It is an arithmetic number, because the mean of its divisors is an integer number (68551116480).

Almost surely, 2^821701994523 is an apocalyptic number.

821701994523 is a deficient number, since it is larger than the sum of its proper divisors (275115869157).

821701994523 is a wasteful number, since it uses less digits than its factorization.

821701994523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45538.

The product of its (nonzero) digits is 1088640, while the sum is 51.

The spelling of 821701994523 in words is "eight hundred twenty-one billion, seven hundred one million, nine hundred ninety-four thousand, five hundred twenty-three".