405561816 has 80 divisors (see below), whose sum is σ = 1239238440. Its totient is φ = 122895360.

The previous prime is 405561799. The next prime is 405561817. The reversal of 405561816 is 618165504.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405561817) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 21321 + ... + 35576.

Almost surely, 2^405561816 is an apocalyptic number.

It is an amenable number.

405561816 is an abundant number, since it is smaller than the sum of its proper divisors (833676624).

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

405561816 is a wasteful number, since it uses less digits than its factorization.

405561816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56926 (or 56913 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 405561816 is about 20138.5653908117. The cubic root of 405561816 is about 740.2055771669.

The spelling of 405561816 in words is "four hundred five million, five hundred sixty-one thousand, eight hundred sixteen".