306405820 has 72 divisors (see below), whose sum is σ = 758936304. Its totient is φ = 103590144.

The previous prime is 306405817. The next prime is 306405857. The reversal of 306405820 is 28504603.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69399 + ... + 73681.

It is an arithmetic number, because the mean of its divisors is an integer number (10540782).

Almost surely, 2^306405820 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 306405820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379468152).

306405820 is an abundant number, since it is smaller than the sum of its proper divisors (452530484).

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

306405820 is a wasteful number, since it uses less digits than its factorization.

306405820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4379 (or 4370 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 306405820 is about 17504.4514338496. The cubic root of 306405820 is about 674.1641744198.

It can be divided in two parts, 306 and 405820, that multiplied together give a triangular number (124180920 = T₁₅₇₅₉).

The spelling of 306405820 in words is "three hundred six million, four hundred five thousand, eight hundred twenty".