405665216 has 56 divisors (see below), whose sum is σ = 882213120. Its totient is φ = 183545600.

The previous prime is 405665213. The next prime is 405665231. The reversal of 405665216 is 612566504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405665213) 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, 167051 + ... + 169461.

Almost surely, 2^405665216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 405665216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (441106560).

405665216 is an abundant number, since it is smaller than the sum of its proper divisors (476547904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

405665216 is a wasteful number, since it uses less digits than its factorization.

405665216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2673 (or 2663 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 405665216 is about 20141.1324408535. The cubic root of 405665216 is about 740.2684781847.

The spelling of 405665216 in words is "four hundred five million, six hundred sixty-five thousand, two hundred sixteen".