400020005 has 32 divisors (see below), whose sum is σ = 608318208. Its totient is φ = 245260800.

The previous prime is 400019999. The next prime is 400020007. The reversal of 400020005 is 500020004.

It is not a de Polignac number, because 400020005 - 2¹⁶ = 399954469 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (11).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400020007) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 14969 + ... + 32001.

It is an arithmetic number, because the mean of its divisors is an integer number (19009944).

Almost surely, 2^400020005 is an apocalyptic number.

It is an amenable number.

400020005 is a deficient number, since it is larger than the sum of its proper divisors (208298203).

400020005 is a wasteful number, since it uses less digits than its factorization.

400020005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17117.

The product of its (nonzero) digits is 40, while the sum is 11.

The square root of 400020005 is about 20000.5001187470. The cubic root of 400020005 is about 736.8185826983.

Adding to 400020005 its reverse (500020004), we get a palindrome (900040009).

Subtracting 400020005 from its reverse (500020004), we obtain a palindrome (99999999).

It can be divided in two parts, 40002000 and 5, that multiplied together give a triangular number (200010000 = T₂₀₀₀₀).

The spelling of 400020005 in words is "four hundred million, twenty thousand, five".