8107821 has 6 divisors (see below), whose sum is σ = 11711310. Its totient is φ = 5405208.

The previous prime is 8107817. The next prime is 8107823. The reversal of 8107821 is 1287018.

It can be written as a sum of positive squares in only one way, i.e., 7918596 + 189225 = 2814^2 + 435^2 .

It is not a de Polignac number, because 8107821 - 2² = 8107817 is a prime.

It is a super-2 number, since 2×8107821² = 131473522736082, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8107823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 450426 + ... + 450443.

It is an arithmetic number, because the mean of its divisors is an integer number (1951885).

Almost surely, 2^8107821 is an apocalyptic number.

It is an amenable number.

8107821 is a deficient number, since it is larger than the sum of its proper divisors (3603489).

8107821 is a wasteful number, since it uses less digits than its factorization.

8107821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 900875 (or 900872 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 8107821 is about 2847.4235722843. The cubic root of 8107821 is about 200.8945017025.

The spelling of 8107821 in words is "eight million, one hundred seven thousand, eight hundred twenty-one".