400009824 has 72 divisors (see below), whose sum is σ = 1144640952. Its totient is φ = 132503040.

The previous prime is 400009823. The next prime is 400009837. The reversal of 400009824 is 428900004.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400009823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42684 + ... + 51204.

It is an arithmetic number, because the mean of its divisors is an integer number (15897791).

Almost surely, 2^400009824 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 400009824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (572320476).

400009824 is an abundant number, since it is smaller than the sum of its proper divisors (744631128).

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

400009824 is a wasteful number, since it uses less digits than its factorization.

400009824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8700 (or 8689 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 400009824 is about 20000.2455984920. The cubic root of 400009824 is about 736.8123316663.

Adding to 400009824 its reverse (428900004), we get a palindrome (828909828).

The spelling of 400009824 in words is "four hundred million, nine thousand, eight hundred twenty-four".