20428513816865 has 64 divisors (see below), whose sum is σ = 32372695208448. Its totient is φ = 11981233766400.

The previous prime is 20428513816787. The next prime is 20428513816871. The reversal of 20428513816865 is 56861831582402.

It is not a de Polignac number, because 20428513816865 - 2³⁴ = 20411333947681 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17613485 + ... + 18737445.

It is an arithmetic number, because the mean of its divisors is an integer number (505823362632).

Almost surely, 2^{20428513816865} is an apocalyptic number.

It is an amenable number.

20428513816865 is a deficient number, since it is larger than the sum of its proper divisors (11944181391583).

20428513816865 is a wasteful number, since it uses less digits than its factorization.

20428513816865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126778.

The product of its (nonzero) digits is 22118400, while the sum is 59.

The spelling of 20428513816865 in words is "twenty trillion, four hundred twenty-eight billion, five hundred thirteen million, eight hundred sixteen thousand, eight hundred sixty-five".