20005380 has 120 divisors (see below), whose sum is σ = 64216152. Its totient is φ = 5211648.

The previous prime is 20005369. The next prime is 20005393. The reversal of 20005380 is 8350002.

It can be written as a sum of positive squares in 4 ways, for example, as 1498176 + 18507204 = 1224^2 + 4302^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 85744 + ... + 85976.

Almost surely, 2^20005380 is an apocalyptic number.

20005380 is a gapful number since it is divisible by the number (20) 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 20005380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32108076).

20005380 is an abundant number, since it is smaller than the sum of its proper divisors (44210772).

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

20005380 is a wasteful number, since it uses less digits than its factorization.

20005380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 296 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20005380 is about 4472.7374168399. The cubic root of 20005380 is about 271.4660987554.

Adding to 20005380 its reverse (8350002), we get a palindrome (28355382).

The spelling of 20005380 in words is "twenty million, five thousand, three hundred eighty".