400400100 has 243 divisors, whose sum is σ = 1358771323. Its totient is φ = 98609280.

The previous prime is 400400081. The next prime is 400400113. The reversal of 400400100 is 1004004.

The square root of 400400100 is 20010.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 5503716 + 394896384 = 2346^2 + 19872^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 13806886 + ... + 13806914.

Almost surely, 2^400400100 is an apocalyptic number.

400400100 is the 20010-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400400100

400400100 is an abundant number, since it is smaller than the sum of its proper divisors (958371223).

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

400400100 is a wasteful number, since it uses less digits than its factorization.

400400100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The cubic root of 400400100 is about 737.0518813657.

Multiplying 400400100 by its product of nonzero digits (16), we get a square (6406401600 = 80040²).

Adding to 400400100 its reverse (1004004), we get a palindrome (401404104).

Multiplying 400400100 by its reverse (1004004), we get a square (402003302000400 = 20050020²).

The spelling of 400400100 in words is "four hundred million, four hundred thousand, one hundred".