821872183397 has 2 divisors, whose sum is σ = 821872183398. Its totient is φ = 821872183396.

The previous prime is 821872183339. The next prime is 821872183399. The reversal of 821872183397 is 793381278128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 792044820961 + 29827362436 = 889969^2 + 172706^2 .

It is a cyclic number.

It is not a de Polignac number, because 821872183397 - 2¹² = 821872179301 is a prime.

Together with 821872183399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821872183399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410936091698 + 410936091699.

It is an arithmetic number, because the mean of its divisors is an integer number (410936091699).

Almost surely, 2^821872183397 is an apocalyptic number.

It is an amenable number.

821872183397 is a deficient number, since it is larger than the sum of its proper divisors (1).

821872183397 is an equidigital number, since it uses as much as digits as its factorization.

821872183397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8128512, while the sum is 59.

The spelling of 821872183397 in words is "eight hundred twenty-one billion, eight hundred seventy-two million, one hundred eighty-three thousand, three hundred ninety-seven".