400242420421 has 4 divisors (see below), whose sum is σ = 400259984652. Its totient is φ = 400224856192.

The previous prime is 400242420337. The next prime is 400242420427. The reversal of 400242420421 is 124024242004.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 282566664900 + 117675755521 = 531570^2 + 343039^2 .

It is a cyclic number.

It is not a de Polignac number, because 400242420421 - 2⁷ = 400242420293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400242420427) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 8747890 + ... + 8793523.

It is an arithmetic number, because the mean of its divisors is an integer number (100064996163).

Almost surely, 2^400242420421 is an apocalyptic number.

It is an amenable number.

400242420421 is a deficient number, since it is larger than the sum of its proper divisors (17564231).

400242420421 is a wasteful number, since it uses less digits than its factorization.

400242420421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17564230.

The product of its (nonzero) digits is 4096, while the sum is 25.

Adding to 400242420421 its reverse (124024242004), we get a palindrome (524266662425).

The spelling of 400242420421 in words is "four hundred billion, two hundred forty-two million, four hundred twenty thousand, four hundred twenty-one".