821794512231 has 192 divisors, whose sum is σ = 1598864117760. Its totient is φ = 393823296000.

The previous prime is 821794512223. The next prime is 821794512233. The reversal of 821794512231 is 132215497128.

821794512231 is a `hidden beast` number, since 8 + 2 + 17 + 94 + 512 + 2 + 31 = 666.

It is not a de Polignac number, because 821794512231 - 2³ = 821794512223 is a prime.

It is a super-2 number, since 2×821794512231² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821794512233) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 373033176 + ... + 373035378.

It is an arithmetic number, because the mean of its divisors is an integer number (8327417280).

Almost surely, 2^821794512231 is an apocalyptic number.

821794512231 is a deficient number, since it is larger than the sum of its proper divisors (777069605529).

821794512231 is a wasteful number, since it uses less digits than its factorization.

821794512231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2978 (or 2975 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

It can be divided in two parts, 821794 and 512231, that added together give a square (1334025 = 1155²).

The spelling of 821794512231 in words is "eight hundred twenty-one billion, seven hundred ninety-four million, five hundred twelve thousand, two hundred thirty-one".