20918470689 has 48 divisors (see below), whose sum is σ = 31458392784. Its totient is φ = 13387161600.

The previous prime is 20918470673. The next prime is 20918470691. The reversal of 20918470689 is 98607481902.

20918470689 is a `hidden beast` number, since 2 + 0 + 91 + 8 + 470 + 6 + 89 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 2919565089 + 17998905600 = 54033^2 + 134160^2 .

It is not a de Polignac number, because 20918470689 - 2⁴ = 20918470673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20918470289) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3884779 + ... + 3890159.

It is an arithmetic number, because the mean of its divisors is an integer number (655383183).

Almost surely, 2^20918470689 is an apocalyptic number.

It is an amenable number.

20918470689 is a deficient number, since it is larger than the sum of its proper divisors (10539922095).

20918470689 is a wasteful number, since it uses less digits than its factorization.

20918470689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5618 (or 5615 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 20918470689 in words is "twenty billion, nine hundred eighteen million, four hundred seventy thousand, six hundred eighty-nine".