20517876451 has 4 divisors (see below), whose sum is σ = 21018312504. Its totient is φ = 20017440400.

The previous prime is 20517876439. The next prime is 20517876523. The reversal of 20517876451 is 15467871502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20517876451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20517876251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 250217965 + ... + 250218046.

It is an arithmetic number, because the mean of its divisors is an integer number (5254578126).

Almost surely, 2^20517876451 is an apocalyptic number.

20517876451 is a deficient number, since it is larger than the sum of its proper divisors (500436053).

20517876451 is an equidigital number, since it uses as much as digits as its factorization.

20517876451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500436052.

The product of its (nonzero) digits is 470400, while the sum is 46.

The spelling of 20517876451 in words is "twenty billion, five hundred seventeen million, eight hundred seventy-six thousand, four hundred fifty-one".