400520064 has 128 divisors (see below), whose sum is σ = 1227916800. Its totient is φ = 113301504.

The previous prime is 400520059. The next prime is 400520077. The reversal of 400520064 is 460025004.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 400520064.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 292309 + ... + 293675.

It is an arithmetic number, because the mean of its divisors is an integer number (9593100).

Almost surely, 2^400520064 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 400520064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (613958400).

400520064 is an abundant number, since it is smaller than the sum of its proper divisors (827396736).

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

400520064 is a wasteful number, since it uses less digits than its factorization.

400520064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1500 (or 1488 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 400520064 is about 20012.9973767050. The cubic root of 400520064 is about 737.1254834643.

Adding to 400520064 its reverse (460025004), we get a palindrome (860545068).

The spelling of 400520064 in words is "four hundred million, five hundred twenty thousand, sixty-four".