20728266716381 has 4 divisors (see below), whose sum is σ = 23689447675872. Its totient is φ = 17767085756892.

The previous prime is 20728266716357. The next prime is 20728266716389. The reversal of 20728266716381 is 18361766282702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20728266716381 - 2³⁰ = 20727192974557 is a prime.

It is a super-2 number, since 2×20728266716381² (a number of 27 digits) contains 22 as substring.

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 20728266716381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728266716389) 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, 1480590479735 + ... + 1480590479748.

It is an arithmetic number, because the mean of its divisors is an integer number (5922361918968).

Almost surely, 2^{20728266716381} is an apocalyptic number.

It is an amenable number.

20728266716381 is a deficient number, since it is larger than the sum of its proper divisors (2961180959491).

20728266716381 is an equidigital number, since it uses as much as digits as its factorization.

20728266716381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2961180959490.

The product of its (nonzero) digits is 16257024, while the sum is 59.

The spelling of 20728266716381 in words is "twenty trillion, seven hundred twenty-eight billion, two hundred sixty-six million, seven hundred sixteen thousand, three hundred eighty-one".