821354273721 has 12 divisors (see below), whose sum is σ = 1186418741248. Its totient is φ = 547561151064.

The previous prime is 821354273689. The next prime is 821354273731. The reversal of 821354273721 is 127372453128.

821354273721 is a `hidden beast` number, since 8 + 2 + 1 + 354 + 273 + 7 + 21 = 666.

It is not a de Polignac number, because 821354273721 - 2⁵ = 821354273689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821354273731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42865 + ... + 1282398.

Almost surely, 2^821354273721 is an apocalyptic number.

It is an amenable number.

821354273721 is a deficient number, since it is larger than the sum of its proper divisors (365064467527).

821354273721 is a wasteful number, since it uses less digits than its factorization.

821354273721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1394132 (or 1394129 counting only the distinct ones).

The product of its digits is 564480, while the sum is 45.

The spelling of 821354273721 in words is "eight hundred twenty-one billion, three hundred fifty-four million, two hundred seventy-three thousand, seven hundred twenty-one".