20428513816551 has 4 divisors (see below), whose sum is σ = 27238018422072. Its totient is φ = 13619009211032.

The previous prime is 20428513816537. The next prime is 20428513816573. The reversal of 20428513816551 is 15561831582402.

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 20428513816551 - 2²⁶ = 20428446707687 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20428513816494 and 20428513816503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20428513816531) 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, 3404752302756 + ... + 3404752302761.

It is an arithmetic number, because the mean of its divisors is an integer number (6809504605518).

Almost surely, 2^{20428513816551} is an apocalyptic number.

20428513816551 is a deficient number, since it is larger than the sum of its proper divisors (6809504605521).

20428513816551 is an equidigital number, since it uses as much as digits as its factorization.

20428513816551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6809504605520.

The product of its (nonzero) digits is 2304000, while the sum is 51.

The spelling of 20428513816551 in words is "twenty trillion, four hundred twenty-eight billion, five hundred thirteen million, eight hundred sixteen thousand, five hundred fifty-one".