20209191 has 8 divisors (see below), whose sum is σ = 27212784. Its totient is φ = 13339200.

The previous prime is 20209169. The next prime is 20209199. The reversal of 20209191 is 19190202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-20209191 is a prime.

It is a super-2 number, since 2×20209191² = 816822801748962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20209199) 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 7 ways as a sum of consecutive naturals, for example, 33046 + ... + 33651.

It is an arithmetic number, because the mean of its divisors is an integer number (3401598).

Almost surely, 2^20209191 is an apocalyptic number.

20209191 is a deficient number, since it is larger than the sum of its proper divisors (7003593).

20209191 is a wasteful number, since it uses less digits than its factorization.

20209191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66801.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 20209191 is about 4495.4633798976. The cubic root of 20209191 is about 272.3848673350.

Multiplying 20209191 by its sum of digits (24), we get a palindrome (485020584).

Adding to 20209191 its reverse (19190202), we get a palindrome (39399393).

It can be divided in two parts, 2020 and 9191, that added together give a palindrome (11211).

The spelling of 20209191 in words is "twenty million, two hundred nine thousand, one hundred ninety-one".