405442021 has 8 divisors (see below), whose sum is σ = 411645888. Its totient is φ = 399252000.

The previous prime is 405442001. The next prime is 405442031. The reversal of 405442021 is 120244504.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 405442021 - 2¹¹ = 405439973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 405441983 and 405442001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405442001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66001 + ... + 71881.

It is an arithmetic number, because the mean of its divisors is an integer number (51455736).

Almost surely, 2^405442021 is an apocalyptic number.

It is an amenable number.

405442021 is a deficient number, since it is larger than the sum of its proper divisors (6203867).

405442021 is an equidigital number, since it uses as much as digits as its factorization.

405442021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6923.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 405442021 is about 20135.5909026778. The cubic root of 405442021 is about 740.1326892570.

Adding to 405442021 its reverse (120244504), we get a palindrome (525686525).

The spelling of 405442021 in words is "four hundred five million, four hundred forty-two thousand, twenty-one".