820187421 has 32 divisors (see below), whose sum is σ = 1175731200. Its totient is φ = 507070080.

The previous prime is 820187419. The next prime is 820187437. The reversal of 820187421 is 124781028.

It is a happy number.

It is not a de Polignac number, because 820187421 - 2¹ = 820187419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820187441) 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 31 ways as a sum of consecutive naturals, for example, 542056 + ... + 543566.

It is an arithmetic number, because the mean of its divisors is an integer number (36741600).

Almost surely, 2^820187421 is an apocalyptic number.

It is an amenable number.

820187421 is a deficient number, since it is larger than the sum of its proper divisors (355543779).

820187421 is a wasteful number, since it uses less digits than its factorization.

820187421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1729.

The product of its (nonzero) digits is 7168, while the sum is 33.

The square root of 820187421 is about 28638.9144521925. The cubic root of 820187421 is about 936.0614675372.

The spelling of 820187421 in words is "eight hundred twenty million, one hundred eighty-seven thousand, four hundred twenty-one".