405890820 has 72 divisors (see below), whose sum is σ = 1233925056. Its totient is φ = 107998272.

The previous prime is 405890791. The next prime is 405890831. The reversal of 405890820 is 28098504.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88299 + ... + 92781.

It is an arithmetic number, because the mean of its divisors is an integer number (17137848).

Almost surely, 2^405890820 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 405890820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (616962528).

405890820 is an abundant number, since it is smaller than the sum of its proper divisors (828034236).

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

405890820 is a wasteful number, since it uses less digits than its factorization.

405890820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5001 (or 4996 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 405890820 is about 20146.7322412346. The cubic root of 405890820 is about 740.4056821099.

The spelling of 405890820 in words is "four hundred five million, eight hundred ninety thousand, eight hundred twenty".