20649191 has 2 divisors, whose sum is σ = 20649192. Its totient is φ = 20649190.

The previous prime is 20649173. The next prime is 20649217. The reversal of 20649191 is 19194602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20649191 - 2¹⁰ = 20648167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20649991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10324595 + 10324596.

It is an arithmetic number, because the mean of its divisors is an integer number (10324596).

Almost surely, 2^20649191 is an apocalyptic number.

20649191 is a deficient number, since it is larger than the sum of its proper divisors (1).

20649191 is an equidigital number, since it uses as much as digits as its factorization.

20649191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 20649191 is about 4544.1380920918. The cubic root of 20649191 is about 274.3475042799.

The spelling of 20649191 in words is "twenty million, six hundred forty-nine thousand, one hundred ninety-one".