20643380 has 24 divisors (see below), whose sum is σ = 43551648. Its totient is φ = 8219168.

The previous prime is 20643379. The next prime is 20643407. The reversal of 20643380 is 8334602.

It is a super-2 number, since 2×20643380² = 852298275648800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2267 + ... + 6813.

It is an arithmetic number, because the mean of its divisors is an integer number (1814652).

Almost surely, 2^20643380 is an apocalyptic number.

20643380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20643380 is an abundant number, since it is smaller than the sum of its proper divisors (22908268).

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

20643380 is a wasteful number, since it uses less digits than its factorization.

20643380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4783 (or 4781 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 20643380 is about 4543.4986519201. The cubic root of 20643380 is about 274.3217666627.

Adding to 20643380 its reverse (8334602), we get a palindrome (28977982).

The spelling of 20643380 in words is "twenty million, six hundred forty-three thousand, three hundred eighty".