20818919547 has 12 divisors (see below), whose sum is σ = 30136728544. Its totient is φ = 13849300080.

The previous prime is 20818919521. The next prime is 20818919551. The reversal of 20818919547 is 74591981802.

It is a happy number.

20818919547 is a `hidden beast` number, since 2 + 0 + 8 + 1 + 8 + 91 + 9 + 547 = 666.

It is not a de Polignac number, because 20818919547 - 2⁸ = 20818919291 is a prime.

It is a super-2 number, since 2×20818919547² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20818919493 and 20818919502.

It is not an unprimeable number, because it can be changed into a prime (20818919587) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2493904 + ... + 2502237.

Almost surely, 2^20818919547 is an apocalyptic number.

20818919547 is a deficient number, since it is larger than the sum of its proper divisors (9317808997).

20818919547 is a wasteful number, since it uses less digits than its factorization.

20818919547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4996610 (or 4996607 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 54.

The spelling of 20818919547 in words is "twenty billion, eight hundred eighteen million, nine hundred nineteen thousand, five hundred forty-seven".