20257820 has 48 divisors (see below), whose sum is σ = 46853856. Its totient is φ = 7356800.

The previous prime is 20257817. The next prime is 20257837. The reversal of 20257820 is 2875202.

It is a self number, because there is not a number n which added to its sum of digits gives 20257820.

It is a congruent number.

It is an unprimeable number.

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, 26240 + ... + 27000.

It is an arithmetic number, because the mean of its divisors is an integer number (976122).

Almost surely, 2^20257820 is an apocalyptic number.

20257820 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 20257820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23426928).

20257820 is an abundant number, since it is smaller than the sum of its proper divisors (26596036).

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

20257820 is a wasteful number, since it uses less digits than its factorization.

20257820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803 (or 779 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 26.

The square root of 20257820 is about 4500.8688050198. The cubic root of 20257820 is about 272.6031705403.

The spelling of 20257820 in words is "twenty million, two hundred fifty-seven thousand, eight hundred twenty".