20945191 has 4 divisors (see below), whose sum is σ = 21210400. Its totient is φ = 20679984.

The previous prime is 20945167. The next prime is 20945209. The reversal of 20945191 is 19154902.

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 20945191 - 2¹⁷ = 20814119 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 (20945101) 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, 132486 + ... + 132643.

It is an arithmetic number, because the mean of its divisors is an integer number (5302600).

Almost surely, 2^20945191 is an apocalyptic number.

20945191 is a deficient number, since it is larger than the sum of its proper divisors (265209).

20945191 is an equidigital number, since it uses as much as digits as its factorization.

20945191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265208.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 20945191 is about 4576.5916357045. The cubic root of 20945191 is about 275.6521864954.

The spelling of 20945191 in words is "twenty million, nine hundred forty-five thousand, one hundred ninety-one".