400531520 has 28 divisors (see below), whose sum is σ = 953766444. Its totient is φ = 160212480.

The previous prime is 400531513. The next prime is 400531531. The reversal of 400531520 is 25135004.

It can be written as a sum of positive squares in 2 ways, for example, as 209207296 + 191324224 = 14464^2 + 13832^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 400531492 and 400531501.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 625511 + ... + 626150.

Almost surely, 2^400531520 is an apocalyptic number.

400531520 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400531520 is an abundant number, since it is smaller than the sum of its proper divisors (553234924).

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

400531520 is a wasteful number, since it uses less digits than its factorization.

400531520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1251678 (or 1251668 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 400531520 is about 20013.2835886568. The cubic root of 400531520 is about 737.1325113511.

Adding to 400531520 its reverse (25135004), we get a palindrome (425666524).

The spelling of 400531520 in words is "four hundred million, five hundred thirty-one thousand, five hundred twenty".