20670491665 has 16 divisors (see below), whose sum is σ = 25556560128. Its totient is φ = 16041308416.

The previous prime is 20670491627. The next prime is 20670491693. The reversal of 20670491665 is 56619407602.

It is a cyclic number.

It is not a de Polignac number, because 20670491665 - 2²³ = 20662103057 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 362647 + ... + 415756.

It is an arithmetic number, because the mean of its divisors is an integer number (1597285008).

Almost surely, 2^20670491665 is an apocalyptic number.

It is an amenable number.

20670491665 is a deficient number, since it is larger than the sum of its proper divisors (4886068463).

20670491665 is a wasteful number, since it uses less digits than its factorization.

20670491665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778568.

The product of its (nonzero) digits is 544320, while the sum is 46.

The spelling of 20670491665 in words is "twenty billion, six hundred seventy million, four hundred ninety-one thousand, six hundred sixty-five".