400240020 has 192 divisors, whose sum is σ = 1235243520. Its totient is φ = 96509952.

The previous prime is 400240019. The next prime is 400240021. The reversal of 400240020 is 20042004.

It is an interprime number because it is at equal distance from previous prime (400240019) and next prime (400240021).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 400239978 and 400240005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400240021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2921392 + ... + 2921528.

It is an arithmetic number, because the mean of its divisors is an integer number (6433560).

Almost surely, 2^400240020 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 400240020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (617621760).

400240020 is an abundant number, since it is smaller than the sum of its proper divisors (835003500).

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

400240020 is a wasteful number, since it uses less digits than its factorization.

400240020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 272 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 12.

The square root of 400240020 is about 20005.9996001200. Note that the first 3 decimals coincide. The cubic root of 400240020 is about 736.9536438008.

Adding to 400240020 its reverse (20042004), we get a palindrome (420282024).

The spelling of 400240020 in words is "four hundred million, two hundred forty thousand, twenty".