400043520 has 240 divisors, whose sum is σ = 1407566160. Its totient is φ = 104988672.

The previous prime is 400043513. The next prime is 400043521. The reversal of 400043520 is 25340004.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 400043493 and 400043502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400043521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2234791 + ... + 2234969.

It is an arithmetic number, because the mean of its divisors is an integer number (5864859).

Almost surely, 2^400043520 is an apocalyptic number.

400043520 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400043520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (703783080).

400043520 is an abundant number, since it is smaller than the sum of its proper divisors (1007522640).

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

400043520 is a wasteful number, since it uses less digits than its factorization.

400043520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 286 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 400043520 is about 20001.0879704080. The cubic root of 400043520 is about 736.8330202675.

Adding to 400043520 its reverse (25340004), we get a palindrome (425383524).

The spelling of 400043520 in words is "four hundred million, forty-three thousand, five hundred twenty".