20403251 has 16 divisors (see below), whose sum is σ = 23016960. Its totient is φ = 17927520.

The previous prime is 20403241. The next prime is 20403293. The reversal of 20403251 is 15230402.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20403251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20403221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45836 + ... + 46278.

It is an arithmetic number, because the mean of its divisors is an integer number (1438560).

Almost surely, 2^20403251 is an apocalyptic number.

20403251 is a deficient number, since it is larger than the sum of its proper divisors (2613709).

20403251 is a wasteful number, since it uses less digits than its factorization.

20403251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20403251 is about 4516.9957936664. The cubic root of 20403251 is about 273.2539555676.

Adding to 20403251 its reverse (15230402), we get a palindrome (35633653).

The spelling of 20403251 in words is "twenty million, four hundred three thousand, two hundred fifty-one".