20504304251 has 4 divisors (see below), whose sum is σ = 20504733504. Its totient is φ = 20503875000.

The previous prime is 20504304199. The next prime is 20504304277. The reversal of 20504304251 is 15240340502.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20504304251 - 2⁶ = 20504304187 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20504304251.

It is not an unprimeable number, because it can be changed into a prime (20504304281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132500 + ... + 242001.

It is an arithmetic number, because the mean of its divisors is an integer number (5126183376).

Almost surely, 2^20504304251 is an apocalyptic number.

20504304251 is a deficient number, since it is larger than the sum of its proper divisors (429253).

20504304251 is an equidigital number, since it uses as much as digits as its factorization.

20504304251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429252.

The product of its (nonzero) digits is 4800, while the sum is 26.

Adding to 20504304251 its reverse (15240340502), we get a palindrome (35744644753).

The spelling of 20504304251 in words is "twenty billion, five hundred four million, three hundred four thousand, two hundred fifty-one".