821683431 has 12 divisors (see below), whose sum is σ = 1214478408. Its totient is φ = 535049424.

The previous prime is 821683409. The next prime is 821683463. The reversal of 821683431 is 134386128.

821683431 is a `hidden beast` number, since 8 + 216 + 8 + 3 + 431 = 666.

It is not a de Polignac number, because 821683431 - 2⁵ = 821683399 is a prime.

It is a super-2 number, since 2×821683431² = 1350327321559863522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821683631) 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, 1061220 + ... + 1061993.

It is an arithmetic number, because the mean of its divisors is an integer number (101206534).

Almost surely, 2^821683431 is an apocalyptic number.

821683431 is a deficient number, since it is larger than the sum of its proper divisors (392794977).

821683431 is a wasteful number, since it uses less digits than its factorization.

821683431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2123262 (or 2123259 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 821683431 is about 28665.0210360990. The cubic root of 821683431 is about 936.6302427266.

The spelling of 821683431 in words is "eight hundred twenty-one million, six hundred eighty-three thousand, four hundred thirty-one".