20766091 has 4 divisors (see below), whose sum is σ = 21050632. Its totient is φ = 20481552.

The previous prime is 20766073. The next prime is 20766101. The reversal of 20766091 is 19066702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19066702 = 2 ⋅9533351.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20766091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20766041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142161 + ... + 142306.

It is an arithmetic number, because the mean of its divisors is an integer number (5262658).

Almost surely, 2^20766091 is an apocalyptic number.

20766091 is a deficient number, since it is larger than the sum of its proper divisors (284541).

20766091 is an equidigital number, since it uses as much as digits as its factorization.

20766091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284540.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 20766091 is about 4556.9826640004. The cubic root of 20766091 is about 274.8642459435.

The spelling of 20766091 in words is "twenty million, seven hundred sixty-six thousand, ninety-one".