817942420 has 48 divisors (see below), whose sum is σ = 1824696720. Its totient is φ = 306919424.

The previous prime is 817942417. The next prime is 817942421. The reversal of 817942420 is 24249718.

It can be written as a sum of positive squares in 8 ways, for example, as 210714256 + 607228164 = 14516^2 + 24642^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 817942420.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817942421) 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 15 ways as a sum of consecutive naturals, for example, 103986 + ... + 111574.

It is an arithmetic number, because the mean of its divisors is an integer number (38014515).

Almost surely, 2^817942420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817942420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (912348360).

817942420 is an abundant number, since it is smaller than the sum of its proper divisors (1006754300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

817942420 is a wasteful number, since it uses less digits than its factorization.

817942420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7932 (or 7930 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 817942420 is about 28599.6926556912. The cubic root of 817942420 is about 935.2066307218.

The spelling of 817942420 in words is "eight hundred seventeen million, nine hundred forty-two thousand, four hundred twenty".