20740257 has 12 divisors (see below), whose sum is σ = 30004260. Its totient is φ = 13805568.

The previous prime is 20740253. The next prime is 20740259. The reversal of 20740257 is 75204702.

20740257 is a `hidden beast` number, since 207 + 402 + 57 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9511056 + 11229201 = 3084^2 + 3351^2 .

It is not a de Polignac number, because 20740257 - 2² = 20740253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20740257.

It is not an unprimeable number, because it can be changed into a prime (20740253) 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, 6369 + ... + 9057.

It is an arithmetic number, because the mean of its divisors is an integer number (2500355).

Almost surely, 2^20740257 is an apocalyptic number.

It is an amenable number.

20740257 is a deficient number, since it is larger than the sum of its proper divisors (9264003).

20740257 is a wasteful number, since it uses less digits than its factorization.

20740257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3552 (or 3549 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 27.

The square root of 20740257 is about 4554.1472308216. The cubic root of 20740257 is about 274.7502172680.

Adding to 20740257 its reverse (75204702), we get a palindrome (95944959).

The spelling of 20740257 in words is "twenty million, seven hundred forty thousand, two hundred fifty-seven".