20290291 has 4 divisors (see below), whose sum is σ = 23188912. Its totient is φ = 17391672.

The previous prime is 20290261. The next prime is 20290297. The reversal of 20290291 is 19209202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19209202 = 2 ⋅9604601.

It is a cyclic number.

It is not a de Polignac number, because 20290291 - 2²¹ = 18193139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20290297) 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, 1449300 + ... + 1449313.

It is an arithmetic number, because the mean of its divisors is an integer number (5797228).

Almost surely, 2^20290291 is an apocalyptic number.

20290291 is a deficient number, since it is larger than the sum of its proper divisors (2898621).

20290291 is an equidigital number, since it uses as much as digits as its factorization.

20290291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2898620.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 20290291 is about 4504.4745531527. The cubic root of 20290291 is about 272.7487434982.

Adding to 20290291 its reverse (19209202), we get a palindrome (39499493).

The spelling of 20290291 in words is "twenty million, two hundred ninety thousand, two hundred ninety-one".