20671820 has 48 divisors (see below), whose sum is σ = 47863200. Its totient is φ = 7455168.

The previous prime is 20671817. The next prime is 20671873. The reversal of 20671820 is 2817602.

It is a super-2 number, since 2×20671820² = 854648284224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 20671820.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 480719 + ... + 480761.

It is an arithmetic number, because the mean of its divisors is an integer number (997150).

Almost surely, 2^20671820 is an apocalyptic number.

20671820 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 20671820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23931600).

20671820 is an abundant number, since it is smaller than the sum of its proper divisors (27191380).

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

20671820 is an equidigital number, since it uses as much as digits as its factorization.

20671820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 20671820 is about 4546.6273214329. The cubic root of 20671820 is about 274.4476848510.

The spelling of 20671820 in words is "twenty million, six hundred seventy-one thousand, eight hundred twenty".