821487212172 has 72 divisors (see below), whose sum is σ = 2265958989840. Its totient is φ = 248864555520.

The previous prime is 821487212171. The next prime is 821487212177. The reversal of 821487212172 is 271212784128.

821487212172 is a `hidden beast` number, since 82 + 1 + 487 + 2 + 1 + 21 + 72 = 666.

It is not an unprimeable number, because it can be changed into a prime (821487212171) 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 23 ways as a sum of consecutive naturals, for example, 1103568 + ... + 1691400.

Almost surely, 2^821487212172 is an apocalyptic number.

It is an amenable number.

821487212172 is an abundant number, since it is smaller than the sum of its proper divisors (1444471777668).

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

821487212172 is a wasteful number, since it uses less digits than its factorization.

821487212172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 591383 (or 591378 counting only the distinct ones).

The product of its digits is 200704, while the sum is 45.

The spelling of 821487212172 in words is "eight hundred twenty-one billion, four hundred eighty-seven million, two hundred twelve thousand, one hundred seventy-two".