20806462991 has 4 divisors (see below), whose sum is σ = 21057143352. Its totient is φ = 20555782632.

The previous prime is 20806462961. The next prime is 20806463011. The reversal of 20806462991 is 19926460802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20806462991 - 2¹⁰ = 20806461967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806462961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125340056 + ... + 125340221.

It is an arithmetic number, because the mean of its divisors is an integer number (5264285838).

Almost surely, 2^20806462991 is an apocalyptic number.

20806462991 is a deficient number, since it is larger than the sum of its proper divisors (250680361).

20806462991 is an equidigital number, since it uses as much as digits as its factorization.

20806462991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250680360.

The product of its (nonzero) digits is 373248, while the sum is 47.

The spelling of 20806462991 in words is "twenty billion, eight hundred six million, four hundred sixty-two thousand, nine hundred ninety-one".