821493171 has 10 divisors (see below), whose sum is σ = 1227168932. Its totient is φ = 547662060.

The previous prime is 821493157. The next prime is 821493187. The reversal of 821493171 is 171394128.

It is a happy number.

It is not a de Polignac number, because 821493171 - 2⁶ = 821493107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821493571) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 5070865 + ... + 5071026.

Almost surely, 2^821493171 is an apocalyptic number.

821493171 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

821493171 is a deficient number, since it is larger than the sum of its proper divisors (405675761).

821493171 is a wasteful number, since it uses less digits than its factorization.

821493171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10141903 (or 10141894 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 821493171 is about 28661.7021650843. The cubic root of 821493171 is about 936.5579452054.

The spelling of 821493171 in words is "eight hundred twenty-one million, four hundred ninety-three thousand, one hundred seventy-one".