20806778545 has 16 divisors (see below), whose sum is σ = 28558827648. Its totient is φ = 14255596800.

The previous prime is 20806778539. The next prime is 20806778569. The reversal of 20806778545 is 54587760802.

It is not a de Polignac number, because 20806778545 - 2³ = 20806778537 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20806778492 and 20806778501.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205459 + ... + 289528.

It is an arithmetic number, because the mean of its divisors is an integer number (1784926728).

Almost surely, 2^20806778545 is an apocalyptic number.

It is an amenable number.

20806778545 is a deficient number, since it is larger than the sum of its proper divisors (7752049103).

20806778545 is a wasteful number, since it uses less digits than its factorization.

20806778545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496200.

The product of its (nonzero) digits is 3763200, while the sum is 52.

The spelling of 20806778545 in words is "twenty billion, eight hundred six million, seven hundred seventy-eight thousand, five hundred forty-five".