405915840 has 224 divisors, whose sum is σ = 1562526720. Its totient is φ = 98380800.

The previous prime is 405915827. The next prime is 405915841. The reversal of 405915840 is 48519504.

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

It is a junction number, because it is equal to n+sod(n) for n = 405915795 and 405915804.

It is not an unprimeable number, because it can be changed into a prime (405915841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92905 + ... + 97175.

Almost surely, 2^405915840 is an apocalyptic number.

405915840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 405915840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781263360).

405915840 is an abundant number, since it is smaller than the sum of its proper divisors (1156610880).

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

405915840 is a wasteful number, since it uses less digits than its factorization.

405915840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4308 (or 4292 counting only the distinct ones).

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

The square root of 405915840 is about 20147.3531760378. The cubic root of 405915840 is about 740.4208952071.

The spelling of 405915840 in words is "four hundred five million, nine hundred fifteen thousand, eight hundred forty".