20257280 has 80 divisors (see below), whose sum is σ = 50012424. Its totient is φ = 7864320.

The previous prime is 20257271. The next prime is 20257297. The reversal of 20257280 is 8275202.

It can be written as a sum of positive squares in 4 ways, for example, as 8202496 + 12054784 = 2864^2 + 3472^2 .

It is a tau number, because it is divible by the number of its divisors (80).

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, 104864 + ... + 105056.

Almost surely, 2^20257280 is an apocalyptic number.

20257280 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 20257280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25006212).

20257280 is an abundant number, since it is smaller than the sum of its proper divisors (29755144).

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

20257280 is an equidigital number, since it uses as much as digits as its factorization.

20257280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 241 counting only the distinct ones).

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

The square root of 20257280 is about 4500.8088162018. The cubic root of 20257280 is about 272.6007483149.

The spelling of 20257280 in words is "twenty million, two hundred fifty-seven thousand, two hundred eighty".