400040002 has 8 divisors (see below), whose sum is σ = 601116300. Its totient is φ = 199667904.

The previous prime is 400039999. The next prime is 400040021. The reversal of 400040002 is 200040004.

It is a Cunningham number, because it is equal to 20001²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 400040001 + 1 = 20001^2 + 1^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174627 + ... + 176902.

Almost surely, 2^400040002 is an apocalyptic number.

400040002 is a deficient number, since it is larger than the sum of its proper divisors (201076298).

400040002 is a wasteful number, since it uses less digits than its factorization.

400040002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352100.

The product of its (nonzero) digits is 32, while the sum is 10.

The square root of 400040002 is about 20001.0000249988. Note that the first 4 decimals coincide. The cubic root of 400040002 is about 736.8308603474.

Adding to 400040002 its reverse (200040004), we get a palindrome (600080006).

The spelling of 400040002 in words is "four hundred million, forty thousand, two".