405504021 has 8 divisors (see below), whose sum is σ = 582262240. Its totient is φ = 249540912.

The previous prime is 405504019. The next prime is 405504031. The reversal of 405504021 is 120405504.

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

It is not a de Polignac number, because 405504021 - 2¹ = 405504019 is a prime.

It is a super-2 number, since 2×405504021² = 328867022094336882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405504031) 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, 5198731 + ... + 5198808.

It is an arithmetic number, because the mean of its divisors is an integer number (72782780).

Almost surely, 2^405504021 is an apocalyptic number.

It is an amenable number.

405504021 is a deficient number, since it is larger than the sum of its proper divisors (176758219).

405504021 is a wasteful number, since it uses less digits than its factorization.

405504021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10397555.

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 405504021 is about 20137.1304062918. The cubic root of 405504021 is about 740.1704142464.

Adding to 405504021 its reverse (120405504), we get a palindrome (525909525).

The spelling of 405504021 in words is "four hundred five million, five hundred four thousand, twenty-one".