408216021 has 8 divisors (see below), whose sum is σ = 549375264. Its totient is φ = 269600400.

The previous prime is 408216001. The next prime is 408216031. The reversal of 408216021 is 120612804.

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

It is not a de Polignac number, because 408216021 - 2¹³ = 408207829 is a prime.

It is a super-3 number, since 3×408216021³ (a number of 27 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 408215982 and 408216000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (408216001) 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, 635530 + ... + 636171.

It is an arithmetic number, because the mean of its divisors is an integer number (68671908).

Almost surely, 2^408216021 is an apocalyptic number.

It is an amenable number.

408216021 is a deficient number, since it is larger than the sum of its proper divisors (141159243).

408216021 is a wasteful number, since it uses less digits than its factorization.

408216021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1271811.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 408216021 is about 20204.3564856691. The cubic root of 408216021 is about 741.8168292396.

Adding to 408216021 its reverse (120612804), we get a palindrome (528828825).

The spelling of 408216021 in words is "four hundred eight million, two hundred sixteen thousand, twenty-one".