20380257 has 12 divisors (see below), whose sum is σ = 29654820. Its totient is φ = 13486848.

The previous prime is 20380253. The next prime is 20380259. The reversal of 20380257 is 75208302.

It can be written as a sum of positive squares in 2 ways, for example, as 15610401 + 4769856 = 3951^2 + 2184^2 .

It is not a de Polignac number, because 20380257 - 2² = 20380253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20380257.

It is not an unprimeable number, because it can be changed into a prime (20380253) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7032 + ... + 9497.

It is an arithmetic number, because the mean of its divisors is an integer number (2471235).

Almost surely, 2^20380257 is an apocalyptic number.

It is an amenable number.

20380257 is a deficient number, since it is larger than the sum of its proper divisors (9274563).

20380257 is a wasteful number, since it uses less digits than its factorization.

20380257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16672 (or 16669 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 20380257 is about 4514.4498003633. The cubic root of 20380257 is about 273.1512666502.

Adding to 20380257 its reverse (75208302), we get a palindrome (95588559).

The spelling of 20380257 in words is "twenty million, three hundred eighty thousand, two hundred fifty-seven".