821223281 has 4 divisors (see below), whose sum is σ = 821568000. Its totient is φ = 820878564.

The previous prime is 821223253. The next prime is 821223307. The reversal of 821223281 is 182322128.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 821223281 - 2¹⁸ = 820961137 is a prime.

It is a super-2 number, since 2×821223281² = 1348815354512809922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821229281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168761 + ... + 173558.

It is an arithmetic number, because the mean of its divisors is an integer number (205392000).

Almost surely, 2^821223281 is an apocalyptic number.

It is an amenable number.

821223281 is a deficient number, since it is larger than the sum of its proper divisors (344719).

821223281 is a wasteful number, since it uses less digits than its factorization.

821223281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344718.

The product of its digits is 3072, while the sum is 29.

The square root of 821223281 is about 28656.9935792295. The cubic root of 821223281 is about 936.4553696682.

The spelling of 821223281 in words is "eight hundred twenty-one million, two hundred twenty-three thousand, two hundred eighty-one".