400240004020 has 24 divisors (see below), whose sum is σ = 840609289800. Its totient is φ = 160075948032.

The previous prime is 400240003993. The next prime is 400240004051. The reversal of 400240004020 is 20400042004.

It can be written as a sum of positive squares in 4 ways, for example, as 14179093776 + 386060910244 = 119076^2 + 621338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 400240003985 and 400240004003.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1089165 + ... + 1409524.

It is an arithmetic number, because the mean of its divisors is an integer number (35025387075).

Almost surely, 2^400240004020 is an apocalyptic number.

It is an amenable number.

400240004020 is an abundant number, since it is smaller than the sum of its proper divisors (440369285780).

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

400240004020 is a wasteful number, since it uses less digits than its factorization.

400240004020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2506707 (or 2506705 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 16.

Adding to 400240004020 its reverse (20400042004), we get a palindrome (420640046024).

The spelling of 400240004020 in words is "four hundred billion, two hundred forty million, four thousand, twenty".