821042451 has 24 divisors (see below), whose sum is σ = 1210169376. Its totient is φ = 536215680.

The previous prime is 821042447. The next prime is 821042479. The reversal of 821042451 is 154240128.

It is not a de Polignac number, because 821042451 - 2² = 821042447 is a prime.

It is a super-2 number, since 2×821042451² = 1348221412688174802, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (821042401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 620871 + ... + 622191.

It is an arithmetic number, because the mean of its divisors is an integer number (50423724).

Almost surely, 2^821042451 is an apocalyptic number.

821042451 is a deficient number, since it is larger than the sum of its proper divisors (389126925).

821042451 is a wasteful number, since it uses less digits than its factorization.

821042451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2683 (or 2680 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 821042451 is about 28653.8383292710. The cubic root of 821042451 is about 936.3866300780.

Adding to 821042451 its reverse (154240128), we get a palindrome (975282579).

The spelling of 821042451 in words is "eight hundred twenty-one million, forty-two thousand, four hundred fifty-one".