20734257 has 16 divisors (see below), whose sum is σ = 28804608. Its totient is φ = 13251840.

The previous prime is 20734253. The next prime is 20734267. The reversal of 20734257 is 75243702.

It is not a de Polignac number, because 20734257 - 2² = 20734253 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20734253) by changing a digit.

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, 9523 + ... + 11495.

It is an arithmetic number, because the mean of its divisors is an integer number (1800288).

Almost surely, 2^20734257 is an apocalyptic number.

It is an amenable number.

20734257 is a deficient number, since it is larger than the sum of its proper divisors (8070351).

20734257 is a wasteful number, since it uses less digits than its factorization.

20734257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2120.

The product of its (nonzero) digits is 11760, while the sum is 30.

The square root of 20734257 is about 4553.4884429413. The cubic root of 20734257 is about 274.7237203238.

Adding to 20734257 its reverse (75243702), we get a palindrome (95977959).

The spelling of 20734257 in words is "twenty million, seven hundred thirty-four thousand, two hundred fifty-seven".