20381820 has 48 divisors (see below), whose sum is σ = 58617888. Its totient is φ = 5287680.

The previous prime is 20381807. The next prime is 20381821. The reversal of 20381820 is 2818302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20381821) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 2371 + ... + 6810.

It is an arithmetic number, because the mean of its divisors is an integer number (1221206).

Almost surely, 2^20381820 is an apocalyptic number.

20381820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20381820 is an abundant number, since it is smaller than the sum of its proper divisors (38236068).

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

20381820 is a wasteful number, since it uses less digits than its factorization.

20381820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9230 (or 9228 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 20381820 is about 4514.6229078407. The cubic root of 20381820 is about 273.1582492987.

The spelling of 20381820 in words is "twenty million, three hundred eighty-one thousand, eight hundred twenty".