20793991 has 4 divisors (see below), whose sum is σ = 20867752. Its totient is φ = 20720232.

The previous prime is 20793989. The next prime is 20794003. The reversal of 20793991 is 19939702.

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 20793991 - 2¹ = 20793989 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 (20793931) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 36456 + ... + 37021.

It is an arithmetic number, because the mean of its divisors is an integer number (5216938).

Almost surely, 2^20793991 is an apocalyptic number.

20793991 is a deficient number, since it is larger than the sum of its proper divisors (73761).

20793991 is an equidigital number, since it uses as much as digits as its factorization.

20793991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73760.

The product of its (nonzero) digits is 30618, while the sum is 40.

The square root of 20793991 is about 4560.0428726055. The cubic root of 20793991 is about 274.9872875666.

The spelling of 20793991 in words is "twenty million, seven hundred ninety-three thousand, nine hundred ninety-one".