405040421 has 4 divisors (see below), whose sum is σ = 407076000. Its totient is φ = 403004844.

The previous prime is 405040417. The next prime is 405040429. The reversal of 405040421 is 124040504.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 405040421 - 2² = 405040417 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 405040393 and 405040402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405040429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1017491 + ... + 1017888.

It is an arithmetic number, because the mean of its divisors is an integer number (101769000).

Almost surely, 2^405040421 is an apocalyptic number.

It is an amenable number.

405040421 is a deficient number, since it is larger than the sum of its proper divisors (2035579).

405040421 is a wasteful number, since it uses less digits than its factorization.

405040421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2035578.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 405040421 is about 20125.6160402607. The cubic root of 405040421 is about 739.8882354947. Note that the first 3 decimals are identical.

Adding to 405040421 its reverse (124040504), we get a palindrome (529080925).

The spelling of 405040421 in words is "four hundred five million, forty thousand, four hundred twenty-one".