821827491 has 16 divisors (see below), whose sum is σ = 1135136160. Its totient is φ = 528254720.

The previous prime is 821827483. The next prime is 821827499. The reversal of 821827491 is 194728128.

It is an interprime number because it is at equal distance from previous prime (821827483) and next prime (821827499).

It is not a de Polignac number, because 821827491 - 2³ = 821827483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821827499) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60001 + ... + 72413.

It is an arithmetic number, because the mean of its divisors is an integer number (70946010).

Almost surely, 2^821827491 is an apocalyptic number.

821827491 is a deficient number, since it is larger than the sum of its proper divisors (313308669).

821827491 is a wasteful number, since it uses less digits than its factorization.

821827491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13206.

The product of its digits is 64512, while the sum is 42.

The square root of 821827491 is about 28667.5337446387. The cubic root of 821827491 is about 936.6849771345.

The spelling of 821827491 in words is "eight hundred twenty-one million, eight hundred twenty-seven thousand, four hundred ninety-one".