1020400420 has 24 divisors (see below), whose sum is σ = 2307675384. Its totient is φ = 376763136.

The previous prime is 1020400417. The next prime is 1020400463. The reversal of 1020400420 is 240040201.

It can be written as a sum of positive squares in 4 ways, for example, as 244109376 + 776291044 = 15624^2 + 27862^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 1020400420.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1962049 + ... + 1962568.

It is an arithmetic number, because the mean of its divisors is an integer number (96153141).

Almost surely, 2^1020400420 is an apocalyptic number.

1020400420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1020400420 is an abundant number, since it is smaller than the sum of its proper divisors (1287274964).

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

1020400420 is a wasteful number, since it uses less digits than its factorization.

1020400420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3924639 (or 3924637 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 1020400420 is about 31943.7070484939. The cubic root of 1020400420 is about 1006.7544151589.

Adding to 1020400420 its reverse (240040201), we get a palindrome (1260440621).

The spelling of 1020400420 in words is "one billion, twenty million, four hundred thousand, four hundred twenty".