821481 has 4 divisors (see below), whose sum is σ = 1095312. Its totient is φ = 547652.

The previous prime is 821479. The next prime is 821489. The reversal of 821481 is 184128.

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 821481 - 2¹ = 821479 is a prime.

It is a super-2 number, since 2×821481² = 1349662066722, which contains 22 as substring.

It is a D-number.

821481 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (821489) 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, 136911 + ... + 136916.

It is an arithmetic number, because the mean of its divisors is an integer number (273828).

2⁸²¹⁴⁸¹ is an apocalyptic number.

It is an amenable number.

821481 is a deficient number, since it is larger than the sum of its proper divisors (273831).

821481 is a wasteful number, since it uses less digits than its factorization.

821481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273830.

The product of its digits is 512, while the sum is 24.

The square root of 821481 is about 906.3558903654. The cubic root of 821481 is about 93.6553319927.

The spelling of 821481 in words is "eight hundred twenty-one thousand, four hundred eighty-one".