405021421 has 16 divisors (see below), whose sum is σ = 485572608. Its totient is φ = 330303600.

The previous prime is 405021403. The next prime is 405021427. The reversal of 405021421 is 124120504.

It is a cyclic number.

It is not a de Polignac number, because 405021421 - 2²⁵ = 371466989 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 (405021427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24166 + ... + 37336.

It is an arithmetic number, because the mean of its divisors is an integer number (30348288).

Almost surely, 2^405021421 is an apocalyptic number.

It is an amenable number.

405021421 is a deficient number, since it is larger than the sum of its proper divisors (80551187).

405021421 is a wasteful number, since it uses less digits than its factorization.

405021421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13392.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 405021421 is about 20125.1439994848. The cubic root of 405021421 is about 739.8766661998.

Adding to 405021421 its reverse (124120504), we get a palindrome (529141925).

The spelling of 405021421 in words is "four hundred five million, twenty-one thousand, four hundred twenty-one".